State of Motion

Q.

How are rest and motion related?

Q.

Sir.... Need some help on.. Why do object seem to being motion when we look outside moving car..... My under understandng is it is because of relative motion. .since I am a observer and in my frame outside object are in relative motion while I am in n driving car.... Is that right understand....

Q. A train is moving with a speed of $40m{s}^{-1}$. On applying the brakes, it comes to rest in $20s$. What is the magnitude of average acceleration of the train?

1. $4m{s}^{-2}$
2. $5m{s}^{-2}$
3. $3m{s}^{-2}$
4. $2m{s}^{-2}$

Q. A pair of equal and opposite forces acting on a body is called:

1. kilopound
2. Dynamo
3. Pivot force
4. Couple

Q.

Which of these is not a property of a true Beam-balance?

1. The pointer of an empty Beam-balance should be vertical.

2. Both arms are of equal length.

3. Both the pans are of equal mass.

4. The pointer of an empty Beam-balance stays horizontal.

Q.

What is the basic unit of time?

Q. Two opposite ends of a cart are attached to two horses respectively. The two horses pull the cart in opposite directions, but it is observed that the position of the cart does not change. What can be the possible explanation?

1. The net force acting on the cart is zero.
2. The direction of the net force acting on the cart is in the vertical direction.
3. The net force acting on the cart is positive.
4. The net force acting on the cart is negative.

Q. In which of the following case(s) can we say that the object is in motion?

1. Only if the object moves away with respect to the observer.
2. If the object doesn't change its position with respect to the observer.
3. If the object changes its position with respect to the observer.
4. Only if the object moves toward with respect to the observer.

Q. When seen from the ground, an apple falling from a tree is under______motion.

1. rectilinear

2. periodic

3. oscillatory

4. circular

Q. Assertion :Bernoulli's equation hold for non-steady or turbulent flows. Reason: In these situations, velocity and pressure are constant with time.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

What happens to the motion of any body after some time, when the directions of it's velocity and acceleration are opposite to each other?

1. Velocity will increase continuosly till acceleration becomes zero.

2. Velocity will decrease and body will come to rest.

3. Velocity will decrease to zero, then it will start moving in the direction of acceleration.

4. Velocity will be changing but it’s speed will be the same.

Q. Atif is going to school with his friend Rashmi in a van which is moving with constant acceleration. Now, answer the following question:
Rashmi, as seen by Atif is:

1. Moving with constant velocity

2. Moving with increasing velocity

3. Moving with decreasing velocity

4. At rest

Q. The S.I. unit of time is .

1. kelvin
2. metre
3. second

Q. Force cannot change the state of motion of a body.

1. True
2. False

Q.

What happens to the motion of a body after some time, when the directions of its velocity and acceleration are opposite to each other?

1. Velocity will decrease and body will come to rest.

2. Velocity will increase continuosly till acceleration becomes zero.

3. Velocity will decrease to zero, then it will start moving in the direction of acceleration.

4. Velocity will be changing but it’s speed will be the same.

Q. In what direction a force should be applied to stop a block moving towards east?

1. East
2. North
3. South
4. West

Q. A pair of equal and opposite forces acting on a body is called:

1. Pivot force
2. Couple
3. kilopound
4. Dynamo

Q. Force cannot bring a stationary body into motion.

1. True
2. False

Q. Two opposite ends of a cart are attached to two horses respectively. The two horses pull the cart in opposite directions, but it is observed that the position of the cart does not change. What can be the possible explanation?

1. The net force acting on the cart is negative.
2. The net force acting on the cart is zero.
3. The direction of the net force acting on the cart is in the vertical direction.
4. The net force acting on the cart is positive.

Q.

Observation 1: Try to stop a ball coming towards you, so as to save a boundary, by applying a force of some magnitude in the opposite direction of the motion of the ball.

Observation 2: In this case apply the force of the same magnitude but in the same direction of the motion of the ball.

In observation 1, the boy saves a boundary by applying a force opposite to the direction of motion, but in observation 2, the change in direction of force cost the team 4 runs as the change in direction of force pushed the ball further to the boundary.

So, the change in the effect of a force can be experienced by a change in its direction as well as magnitude. The above statement is:-

1. True

2. False

Q. In what direction a force should be applied to stop a block moving towards east?

1. East
2. West
3. North
4. South

Q. When a hockey player strikes a moving ball in the direction of its motion, the speed of the ball .

1. decreases
2. increases
3. remains the same

Q. Forces applied to a body bring a change in its state of motion if

1. the body is already in motion.
2. the body is at rest
3. the forces are balanced
4. the forces are unbalanced.

Q. A pair of equal and opposite forces acting on a body is called:

1. Dynamo
2. Pivot force
3. kilopound
4. Couple

Q. We are not crushed under the weight of the air because the pressure inside our body is the atmospheric pressure.

1. lesser than
2. higher than
3. equal to

Q. A pair of equal and opposite forces acting on a body is called:

1. kilopound
2. Pivot force
3. Dynamo
4. Couple

Q. Aman and Raj are travelling in a bus. He sees his friend Mayank on a bike, going in the same direction as that of the bus with the same speed. Who is moving from Raj's point of view?

1. Mayank
2. Aman
3. No one is moving
4. Everyone is moving

Q. Force cannot change the state of motion of a body.

1. True
2. False

Q. What happens to the motion of a body after some time, when the directions of its velocity and acceleration are opposite to each other?

1. Velocity will increase continuosly till acceleration becomes zero.
2. Velocity will decrease only till the object comes to rest.
3. Velocity will decrease to zero, then it will start moving in the direction of acceleration.
4. Velocity will be changing but its speed will be the same.

Q. When a hockey player strikes a moving ball in the direction of its motion, the speed of the ball .

1. increases
2. remains the same
3. decreases