Contact Forces

Q.

Give two examples each of contact and non-contact forces.

Q.

Which of the following is a contact force:
(a) electrostatic force (b) gravitational force
(c) Frictional force (d) magnetic force.

Q.

Friction is a force which opposes relative motion between two surfaces in contact with each other.

1. False

2. True

Q.

Give one example is each case where:
(a) the force is of contact, and
(b) force is at a distance.

Q.

Frictional force always acts in which direction

1. opposite to that of the object in motion

2. in the same direction as that of the object in motion

3. in any direction

4. none of the above

Q.

A man is walking from east to west on a level rough surface road.the force on the man is directed

A)from west to east

B)from east to west

C)along the north

D)along the west

Q.

A force of 10 N acts on a ball moving on a surface. The force of friction that must act between the surface of the ball and the surface so that the ball keeps on moving with constant velocity over the surface must be:

1. 10N

2. 100N

3. Zero

4. 20N

Q.

Classify the following amongst contact and non-contact forces:
(a) frictional force,
(b) Normal reaction
(c) force of tension in a string,
(d) gravitational force,
(e) electrostatic force,
(f) magnetic force.

Q.

Force arises due to the interaction between two objects.

1. True
2. False

Q.

What is known as electrostatic force?

1. Force exerted by a charged body on a charged body only.

2. Force exerted by a charged body on an uncharged body only.

3. Force exerted by a charged body on both charged body and uncharged body.

4. Force which is static.

Q. Assertion(A) : Internal forces do not affect the path and position of an object.
Reason(R) : According to Newton-third law of motion internal forces will occur in equal and opposite pairs so they cancel each other.

1. A) is true but (R) is false. ​

2. Both (A) and (R) are true and (R) is not correct explanation of (A).

3. Both (A) and (R) are true and (R) is correct explanation of (A).

4. (A) is false but (R) is true. ​

Q. For an unbalanced force, the net force acting on the body is equal to zero.

1. True
2. False

Q. For an unbalanced force, the net force acting on the body is equal to zero.

1. True
2. False

Q. If balanced forces are applied on a body initially at rest, then the body ___.

1. remains at rest
2. starts to move
3. moves with a constant speed
4. moves for an instant only

Q. The forces acting on a body are balanced, if the net force is equal to:

1. Infinity
2. 0 N
3. 1 N
4. 0.5 N

Q. force is responsible for stopping a ball rolling on ground.

1. Muscular
2. Gravitational
3. Frictional

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. To keep a body moving with a constant velocity on a frictionless surface, the net force:​

1. Should be zero
2. Should be of variable magnitude​
3. Should act opposite to direction of motion​
4. Should act continuously​

Q. force is responsible for stopping a ball rolling on ground.

1. Muscular
2. Gravitational
3. Frictional

Q. Statement 1: Frictional force can act between surfaces even when they are not in contact.

Statement 2: Friction is a contact force.

1. Statement 1 is true but statement 2 is false.
2. Statement 2 is true but statement 1 is false.
3. Both the statements are true.
4. Both the statements are false.

Q.

Is gravitational potential and friction vector or scalar?

Q. If balanced forces are applied on a body initially at rest, then the body ___.

1. remains at rest
2. starts to move
3. moves with a constant speed
4. moves for an instant only

Q. Statement 1: Frictional force can act between surfaces even when they are not in contact.

Statement 2: Friction is a contact force.

1. Statement 1 is true but statement 2 is false.
2. Statement 2 is true but statement 1 is false.
3. Both the statements are true.
4. Both the statements are false.

Q.

On what factors does the inertia of a body depend? Which has more inertia, an empty tin or a tin of the same size filled with sand?