Contact Forces

Q.

What is a contact force? Give some examples of it and explain why they are contact forces? [3 MARKS]

Q.

Define force of friction.

Q.

(a) What is meant by a contact force? Explain with the help of an example.

(b) What is meant by a no-contact force? Explain with the help of an example.

Q.

if several forces act on a body in a different direction, In which direction body move?

Q. A ball thrown upwards falls back towards the surface of Earth due to force of gravity. The force of gravity is a force.

1. push
2. pull
3. either push or pull

Q.

Interaction of one object with another object results in a force between them.

1. True

2. False

Q.

A car is moving towards North. What will be the direction of the force of friction acting on this car due to the surface of the road?

Q. The force which is responsible for opposing the relative motion of a body is called:

1. Gravitational Force
2. Muscular Force
3. Nuclear Force
4. Frictional force

Q.

Two forces that are equal in magnitude are acting on a body in opposite directions along the same line of action cancel out each other.

1. True

2. False

Q.

Which among the following statement is true?

1. Friction exists between solids only.

2. Friction exists between solids, liquids and gases.

3. Friction exists between liquids only.

4. Friction exists between gases only.

Q.

Why does the shape of an ointment tube change when we squeeze it ?

Q.

Force of friction always acts in the direction:

1. of applied force

2. opposite to the direction of applied force

3. at right angles to the direction applied force

4. none of the above

Q.

Magnetic and electrostatic forces are contact forces.

1. True

2. False

Q.

Which of the following statements is true about the weight of an object?

1. The weight of an object is same as its mass

2. The weight of an object refers to its Inertia

3. The weight of an object is the force with which it is attracted toward the earth.

4. None of these

Q.

Which of the following are contact forces ?
A. Friction B.Gravitational force C.Magnetic force D.Muscular force
(a). A and B (b).B and C (c).A and D (d). B and D

Q.

Look at the pictures given below:

(a)

(b)

(c)

Identify the picture in which friction plays a helpful role.

1. A and B only

2. B and C only

3. A and C only

4. A, B and C

Q. Differentiate between contact and non-contact force. Support your answer with suitable examples.

Q.

During ancient times, people believed that Earth was the centre of the universe and all celestial bodies including the Sun revolved around the Earth. If this hypothesis was to be true, then:

1. Earth is heavier than Sun

2. Sun is heavier than Earth

3. Mass of Earth and Sun should be comparable

4. The sum of masses of all celestial bodies should be comparable to that of the Earth

Q. When a plastic comb is rubbed with hair, it acquires some charges due to which it attracts tiny pieces of paper. The type of charge, which the comb acquires from the hair is ___.

1. Positive
2. Negative
3. $\alpha$
4. $\beta$

Q. Question 6
Which one of the following forces is a contact force?

(a) force of gravity
(b) force of friction
(c) magnetic force
(d) electrostatic force

Q.

Archimedes principle states

1. Buoyant force acting on a body is equal to two times the weight of the fluid displaced by the body.

2. None of the above

3. Buoyant force acting on a body is equal to the weight of the body.

4. Buoyant force acting on a body is equal to weight of the fluid displaced by the body.

Q. Why do the soles of our shoes wear out?

1. Soles are of poor design.
2. Soles are worn out due to friction.
3. Soles are made of poor material.
4. Shoes being too narrow.

Q.

Four containers contain water at same height as shown. Rank them according to pressure exerted at the bottom of containers in ascending order.

1. Gravitational force

2. Buoyant force

3. Both A and B

4. Frictional force

Q.

Question 4 (b)
An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms:

muscular, contact, non-contact, gravity, friction, shape, attraction

(b) The force applied by the archer to stretch the bow is an example of ___ force.

Q.

Give two examples, in which a muscular force changes the direction of a body.

Q.

A train is going north, what is the direction of friction on it?

Q.

What is net force?

Q.

Which of the following requires the application of force?

1. Push and pull of the door

2. Walking on the road

3. Pushing a table

4. Playing tug of war

Q. Question 4 (d)
An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms:

muscular, contact, non-contact, gravity, friction, shape, attraction

(d) While the arrow moves towards its target, the forces acting on it are due to ___ and that due to ___of air.

Q.

Why do the soles of our shoes wear out?