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Question: 1
Why is it dangerous o travel on the roof of a bus
Answer: 1
1-104The friction or drag force due to air acting on upper part of the body of a person standing on roof of a running bus tries to turn over which is dangerous while the lower part of the body is at rest with respect to the roof of the bus
Question: 2
Define centripetal force and give formula
Answer: 2
2-104Centripetal force is a force that keeps a body to move in a circle.
Question: 3
Action and reaction are always equal and opposite
Answer: 3
3-104Action and reaction are equal in magnitude but opposite in direction Action and reactioin do not act on the same body Action is applied on one body due to which an equal and opposite reaction is action on another body. Both of these do not neutralize each other due to which the body will move
Question: 4
why do passengers fall outward of the bus when a bus takes a sharp turn
Answer: 4
4-104When bus takes a sharp turn the passengers fall in the outward direction it is due to the inertia that they want to continue their motion in a straight line and thus fall outward.
Question: 5
What is different between
Answer: 5
5-104Mass and Weight ,Action and Reaction, Sliding and Rolling Friction
Question: 6
What is inertia
Answer: 6
6-104Inertia of a body is its property due to which it resists any change in its state of rest or motion
Question: 7
A horse pushes the cart It the action and reaction are equal and opposite then how does the cart move.
Answer: 7
7-104The horse apply action on the road by his feet the reaction is given b y the road on the horse due to which horse moves. The cart which is tied with the horse will also move.
Question: 8
How can you relate a force with the change of momentum of a body
Answer: 8
8-104When a force acts on a body it produces acceleration in the body and it will be equal to the rate of change of momentum of the body.
Question: 9
What will be the tension in a rope pulled from its ends by two opposite force 100N each
Answer: 9
9-104It will be 100N because string is in equilibrium so applied force and reaction force of string of string that is tension are equal.
Question: 10
What is the law of inertia
Answer: 10
10-104Since Newton's first law of motion deals with the inertial property of matter therefore Newton first law of motion is also known as law of inertia stated as
A body continues its state of rest or of uniform motion in a straight line provided on net force act on it.
Question: 11
Why is the law of conservation of momentum important
Answer: 11
11-104Rockets and jet engines also work on the same principle. With the help of law of conservation of momentum it is possible to calculate force, velocity, acceleration of a body. Many elementary particles are discovered by using law of conservation of momentum.
Question: 12
What is force
Answer: 12
12-104Force is a agency which moves or tends to move stop or tends to stop the motion of a body The force can also change the direction of motion of a
Question: 13
What would happen if all friction disappears
Answer: 13
13-104If all friction disappears, there will be no existence of life.
Question: 14
Find the acceleration that is produced by a 20N force in a mass of 8 kg
Answer: 14
14-104Given Data; m= 8kg
F=20 N
Question: 15
What do you know about following
Answer: 15
15-104Tension in a string, Banking of roads, Braking force, Cream separator.
Question: 16
Describe ways to reduce friction.
Answer: 16
16-104The friction can be reduced by
Making the sliding surface's smooth
Making the fast moving objects a streamline shape (fish shape) such as cars, aero planes etc. This causes the smooth flow of air and thus minimizes air resistance at high speeds.
Lubricating the sliding surfaces.
Using ball bearings or roller bearings because the rolling friction is lesser than the sliding friction.
Question: 17
How does oiling the moving parts of a machine lower friction
Answer: 17
17-104As the friction of liquids is less than friction of solids. So oiling the moving parts of the machines lower the friction.
Question: 18
Describe two situations in which force of friction is needed
Answer: 18
18-104We cannot rite without friction between paper and the pencil
We cannot walk without friction Friction enables us to walk on the ground.
Question: 19
Stretch out your palm and hold a book on it. How much force you neend to prevent the book from falling
Answer: 19
19-104We need a force equal to the weight of book to prevent it from falling
Question: 20
Why spinner of washing machine is made to spin at very high speed
Answer: 20
20-104Because when it spins at high speed the water from wet clothes is forces out through hole due to lack of centripetal force.
Question: 21
State first law of motion
Answer: 21
21-104A body continues its state of rest or of uniform motion in a straight line provided no net force acts. on it. It is also called law of inertia.
Question: 22
Why rolling friction is less than sliding friction
Answer: 22
22-104Rolling friction is the force of friction between a rolling body and a surface over which it rolls. So in rolling friction there is no interlocking in cold welds but in sliding friction there is interlocking The roling objects just roll over each other hence area of contact is less than that of sliding. Thus rolling friction is less than sliding friction.
Question: 23
What is action in above example
Answer: 23
23-104Action is weight of book acting downward on the table.
Question: 24
Calculate the value of force acting on a body of mass 4kg and produces and acceleration of 2ms
Answer: 24
24-104mass=m=4kg
Acceleration=a=2ms
Force=F=?
Question: 25
Write two difference of Mass and Weight.
Answer: 25
25-104Mass: Mass of a body is the quantity of matter that it possesses.
It is a scalar quantity
It does not change by using the place
Mass is denoted by m.
Mass can be find by
formula m=f/m
Unit of mass is kilogram (kg)
Question: 26
When a gun is fired, it recoils.
Answer: 26
26-104Total momentum o the gun and the bullet is zero before the firing. When gun fired, bullet moves in forward direction and gun recoils so theat total momentum after firing also becomes zero according to law of conservation of momentum.
Question: 27
What is an Atwood machine
Answer: 27
27-104Atwood machine is an arrangement of two objects of unequal masses. Both the objects are attached to the ends of a string. The string passes over a frictionless pulley. The arrangement is sometimes used to find the acceleration due to gravity.
Question: 28
Define weight and write its unit
Answer: 28
28-104Weight: Weight of a body is due to the force of gravity acted on it weight of body is eual to the force with which Earth attract it.
Question: 29
To weight of a body 147N. What its mass
Answer: 29
29-104Given Data Weight =w=147N
Gravitational acceleration= g=10ms
mass=m=?
w=mg
Question: 30
A force of 20n moves a body with an acceleration of 2
Answer: 30
30-104Given data Force=F=20N
acceleration =a=2ms
m=?
We know that f=ma
Question: 31
What is meant by tension in a string
Answer: 31
31-104The force acting along a string is called tension in a string
Question: 32
Define newton's second law of motion and give equation
Answer: 32
32-104Statement: When a net force acts on a body it produces acceleration in the body in the direction of the net force. The magnitude of this acceleration is directly proportional to the net force acting on the body and inversely proportional to its mass
Equation: F=ma
Question: 33
State Newton first law of motion
Answer: 33
33-104A body continues its state of rest or of uniform motion in a straight line unless acted upon by a net force.
Question: 34
Find the acceleration that is produced by 20N force in a mass of 8kg
Answer: 34
34-104m=8kg
f=20N
a=?
Using the formula of mass force acceleration
Question: 35
Find the acceleration produced by a force of 100N in a mass of 50kg
Answer: 35
35-104Mass=-m=50kg
Force=f=100N
To Find
Acceleration a=?
Formula: F=ma
a=f/m
puting the value we get
a100N/50kg=100kgm/50kg
a=2ms
Question: 36
What will be the tension in a string that is pulled from its ends by two opposite forces 100N each
Answer: 36
36-104Because force are acting at opposite direction, therefore the net tension is 100N
Question: 37
Is there a reaction in above example
Answer: 37
37-104Yes there is reaction and its direction is in upward direction
Question: 38
What is the difference between action and reaction
Answer: 38
38-104Action: The force exerted by external agency on a system is called action.
Question: 39
Writer two disadvantages and two disadvantages of friction.
Answer: 39
39-104Advantages of friction: It cannot not written if there would be no friction between paper and pencil
Friction enables us to walk on ground We cannot run on a slippery ground because it offers very little friction.
Question: 40
Difference between Mass or Weight.
Answer: 40
40-104Mass: i. Mass of a body is the quantity of matte possessed by the body
2. It is a scalar quantity
3. It is measured by using a common balance.
4. It remains same every where.
5. The SI unit of mass is kilogram
6. It is base quantity.
Question: 41
What is the relation between force and momentum
Answer: 41
41-104The rate of change of momentum of a body is equal to applied force
Equation: F=p1-p1/t
Question: 42
What is isolated system.
Answer: 42
42-104An isolated system is a group of interacting bodies on which no external force is acting.
Question: 43
What is meant by dynamics?
Answer: 43
43-104The branch of mechanics that deals with study of motion of an object and the cause of its motion is called dynamics.
Question: 44
What is meant by Force of Limiting Friction symbol
Answer: 44
44-104Friction: The force that opposes the motion of moving object is called friction.
Question: 45
Define inertia. Describe two of inertia.
Answer: 45
45-104Example 1:
Take a glass cover it with a piece of cardboard. Now kick the card horizontally with a Jerk of your finger. The coin does not move with the cardbeard with the inertia and falls in to the glass
Example 2:
Cut a strip of paper, place it on the table. Stack a few coins at its on end. Stack a few coins at its an end pull out the paperstrip under the coins with a jerk we will succeed in pulling out the paper strip under the stacked coinwithout letting them to fall .
Question: 46
What is the law of inertia?
Answer: 46
46-104Since Newton's first law of motion deals with the inertial property of matter, there fore ,Newton's first law of motion is also known as law of inertia stated as.
A body continues its state of rest or of uniform motion in a straight line provided no net force asct on it.
Question: 47
Write two ways to reduce friction
Answer: 47
47-104Methods of reducing friction
Making the sliding surfaces smooth
Lubricating the sliding surfaces
Using ball bearings to convert sliding into rolling
Reduce the forces acting on the surface
Question: 48
What is action in above example.
Answer: 48
48-104Action is weight of book acting downward on the table.
Question: 49
When a gun is fired it recoils
Answer: 49
49-104As the gun is fired bullet shoots out of the gun and acquires momentum, To conserve momentum of the system, the gun recoils.
Question: 50
Difference between sliding friction and Rolling friction.
Answer: 50
50-104Sliding friction: In sliding friction the surface of a body moves by sliding against the surface of another body.
Question: 51
Define Newton's second law.
Answer: 51
51-104When a force act on body it produce acceleration in the direction of force. The magnitude of acceleration is directly proportional to applied net force.
F = ma
Question: 52
Action and reaction are always equal and opposite. Then how does a body moves ?
Answer: 52
52-104Action and reaction are equal in magnitude butopposite in direction.
Action and reaction do not act on the same body. Action is applied on the body due to which an equal and opposite reaction is acting on another body. Both of these do not neutralize each other due to which the body will move
Question: 53
Action and reaction are always equal and oposite then how does a body move
Answer: 53
53-104Action and reaction are always equal and opposite in direction even then body also moves, it is due to that action and reaction on different bodies.
Question: 54
Action and reaction are always equal and opposite. Then how does a body moves ?
Answer: 54
54-104Action and reaction are equal in magnitude but opposite in direction. Action and reaction do not act on the same body. Action is applied on the body due to which an equal and opposite reaction is acting on another body. Both of these do notneutralize each other due to which the body will move.
Question: 55
What is meant by centrifugal force.
Answer: 55
55-104The reaction of centripetal force is called centrifugal force.
Fc=mv2/r
Question: 56
Why is it dangerous to travel at the roof of a bus
Answer: 56
56-104Because the friction force due air actingon the upper of body of the person who is travelling on the roof of the bus try to turn over which is dangerous for passenger while the lower portion remain at rest w.r.t the roof of the bus
Question: 57
What is Atwood Machine
Answer: 57
57-104Atwood machine: Atwood machine is a system consist of two different masses hanging vertically by the ends of a string passing over a pulley
Question: 58
Define newton, Circular motion?
Answer: 58
58-104Remember that Newton's Second law of Motion States that force is equal to mass times acceleration, and uniform circular motion refers to perfectly circular motion around a center point.
Question: 59
State the principle of motion of Rocket
Answer: 59
59-104A rocket moves on the principle of newton's third law of motion When its fuel burns hopt gases escape out from its tail with a very high speed The reaction of these gases on the rocket causes it to move opposite to the gases rushing out of it to move opposite to the gasses rushing out of its tail.
Question: 60
Which shoes is better for jugging
Answer: 60
60-104The shoes whose grip is strong on ground is better for jugging these shoes provide more friction for strong grip on road and prevent to falling
Question: 61
Define Circular motion:
Answer: 61
61-104If a body move in circular path its motion is known as circular motion.
Question: 62
Why the spanner of washing machine is moved fastly
Answer: 62
62-104The dryer of the washing machine works on the principle of centrifuge. The dryer consists of a long cylinder with hundreds of small holes on its walls wet clothes are piled up in this cylinder when the cylinder is rotated rapidly about its axis water from wet clothes moves outwards to the wall of the cylinder and is drained out through the holes and the clothes become dry quickly
Question: 63
Define limiting frictions.
Answer: 63
63-104The maximum value of static friction is known the force of limiting friction
Fs=μmg
Question: 64
How cream separator work
Answer: 64
64-104Cream separate is a high-speed spinner which acts on the principle of centrifuge machines. The bowl spins at very high speed causing the heavier contents of milk to move outward in the bowl pushing the lighter contents inward towards the spinning axis. Therefore, skimmed milk, which is denser than cream is collected at the outer wall of the bowl the lighter part (cream) is pushed towards the center from where it is collected through pipe
Question: 65
State newton's third law of motion and wite two examples
Answer: 65
65-104Newton's third law of motion: To every action there is always an eual but opposite reaction.
Question: 66
Differentiate between sliding friction and rolling friction.
Answer: 66
66-104Sliding friction: The frictional force produced between a body and surface when it rotates on the surface is called sliding friction.
Question: 67
Why friction opposes motion
Answer: 67
67-104Definition: The force that apposes the motion of moving objects is called friction
Question: 68
When a gun is fired, it recoils, Why?
Answer: 68
68-104Because of Newton third law of motion. When a bullet is fired from a gun the force sending the bullet is equal to the force sending the gun backward.
Question: 69
Define Momentum.
Answer: 69
69-104Momentum of a body is the quantity of motion it possesses due to its mass and velocity.
Formula ; P = m x v
Unit: Kgms-1 or Ns.
Question: 70
How does oiling the moving parts of a machine low as friction
Answer: 70
70-104By applying lubricants (oil or grease) to surfaces they become smooth and friction is reduced As the friction of liquids is less than that of solid surfaces, therefore, oil or grease is applied between the parts of machinery
Question: 71
Define friction.
Answer: 71
71-104The force that opposes the motion of moving object is called friction.
Question: 72
Define centripetal force and centrifugal force.
Answer: 72
72-104Centripetal force: Centripetal force is a force that keeps a body in a circle.
Equation: F=mv/r
Question: 73
Define Tension in a string:
Answer: 73
73-104The force acting along a string is called tension. Its unit is newton . It is represented by 'T'
Question: 74
Define Cream separator:
Answer: 74
74-104Most modern plants use a separator to control the fat contents of various product. A seperator is a high-speed spinner. It acts on the same principle of centrifuge machines.
Question: 75
What is meant by limiting friction
Answer: 75
75-104Limiting Friction: The maximum value of friction is know as the force of limiting friction
Question: 76
Difference between kinematics and Dynamic?
Answer: 76
76-104Kinematics is the study of motion and position, or the geometry of an event.
Question: 77
State first law of motion.
Answer: 77
77-104A body continues its state of rest or of uniform motion in a straight line provided no net force acts on it. It is also called law of inertia.
Question: 78
Describe braking and skidding
Answer: 78
78-104Braking: The force that acts on a moving vehicle to lock up its types is called braking
Question: 79
Define Braking force.
Answer: 79
79-104When we drive a car on a road and we suddenly apply a brake on a wheel of our car. it will stop is called braking.
Question: 80
Define unit of force.
Answer: 80
80-104Unit of force is Newton. 1 N is a force that produced an acceleration of 1 ms-2 in a body of mass of 1 kg.
Question: 81
Define net force.
Answer: 81
81-104Net force is the resultant of all forces acting on a body.
Question: 82
Write two method of reducing friction.
Answer: 82
82-104Making the sliding surfaces smooth
By converting sliding friction into rolling friction.
Question: 83
What is meant by rolling friction?
Answer: 83
83-104The force of friction between a rolling body and a surface over which it rolls is called rolling friction.
Question: 84
Answer: 84
84-104Sliding friction is also known as kinetic friction or moving friction and is defiend as the force that is required to keep a surface sliding along another surface.Resistance to motion by bodies that are in rolling contact
Rolling friction
Question: 85
Define Banking of roads.
Answer: 85
85-104Banking of a road means that the outer edge of a road is raised. Outer edge of the curved road is elevated to prevent skidding.
Question: 86
Define friction and write equation.
Answer: 86
86-104The force that opposes the motion of moving objects is called friction.
Fs=μmg
Question: 87
What would happen if all friction suddenly disappears?
Answer: 87
87-104If all friction suddenly disappears, everyone dies because you can'twalk or do anything.
Question: 88
Why is it dangerous to travel on the roof of a bus.
Answer: 88
88-104The friction or drag force due to air acting on upper part of the body of a person standing on roof of a running bus, tries to turn over which is dangerous while the lower part of the body is rest with respect to the roof of the bus.
Question: 89
State Newton third law of Motion?
Answer: 89
89-104To every action there is always an equal but opposite reaction
Question: 90
Why the spinner of a washing machine is made to spin at a very high speed?
Answer: 90
90-104As the spin of water, water is pulled from the wet clothes through the small holes in the inner-tube into the outer-tube due to centrifugal force. This helps to reduce dry time by leaving your clothes only slightly damp, rather than sopping wet after washing
Question: 91
State Newton Second Law of motion?
Answer: 91
91-104When a net force `F' acts on a body it produces an accelerationin the body direction of force and the magnitude of acceleration id directly proportional to the force and is inversely proportional to the mass of the body.
Question: 92
What is meant by sliding friction.
Answer: 92
92-104When two bodies slid over one another, the force of friction between them is known as sliding friction.
Question: 93
Define Tension in a string, Braking force Momentum?
Answer: 93
93-104TheTension force is the force that is transmitted through a string, rope, cable or wire when itpulled tight by the force acting from opposite ends
Question: 94
State newton's third law of motion.
Answer: 94
94-104To every action there is alwasys an equal but opposite reaction e.g. a launching of rocket.
Question: 95
What is the advantage of bankingof road ?
Answer: 95
95-104When a road is banked in a tight turn a lot of the normal radiationbalances the centrifugal force so that we are not entirely dependent on friction which also force torque and can overturn the vehicle in tight turns.
Question: 96
What will be the tension in a ropethat is pull from its ends by two opposite forces 100N?
Answer: 96
96-104The tension in a rope that is pulledfrom its ends by two opposite forces 100N each will be 100 N
Question: 97
What do you mean by skidding ?
Answer: 97
97-104Motion of wheel without rotation is called skidding.
Question: 98
In which case it is easy for the tireto roll over? Rough ground
Answer: 98
98-104Rough ground:
In case of rough ground, it is difficult for the type the roll over because Question: 99
What are the factor on which friction depends?
Answer: 99
99-104Nature of two surfaces in contact
pressing force between the surfaces in contact.
Question: 100
Why is it easy to roll a cylindrical eraser on a paper sheet than to slide it?
Answer: 100
100-104Because the sliding friction is greater than rolling friction. So rolling is easy than sliding .
Question: 101
A force of 20N moves a body with an acceleration of 2ms-2What is tits mass?
Answer: 101
101-104F= 20Na = 2ms-2m =?m =20/2=10kgMass is 10 kg
F=ma or m = F/a
Question: 102
Difference between Mass and Weight?
Answer: 102
102-104Mass
1- Mass of a body is the quantity of matter possessed by the body
2- It is a scalar quantity
Question: 103
A horse pushes the cart. If the action and reaction are equal and opposites,then how does the cart move?
Answer: 103
103-104When a horse pushes the ground the ground reacts and exerts a force on the horse in the forward direction. The force is able to overcomefriction force of the cart and it moves.
Question: 104
Define Coefficient offriction, cream separator, banking of road ?
Answer: 104
104-104A coefficient of friction is a value that shows the relationship between the force of friction between two objects and the normal reaction between the objects are involved.
