Second Law of Motion

Q.

A bullet of mass $0.04kg$ moving with a speed of 90 m/s enters a heavy wooden block and is stopped after a distance of $60cm$. What is the average force exerted by the block on the bullet?

Q.

According to Newton's second law of motion, force is directly proportional to the rate of change of momentum provided

1. speed of body remains constant

2. velocity of body remains constant

3. mass of body remains constant

4. acceleration of body remains constant

Q. Why is one end of a steel girder in a bridge kept on rollers instead of fixing it in pillar?

Q. Force is a push or pull.

1. True
2. False

Q.

The relationship among force, mass, and acceleration is stated in __________.

Q. You want to lift a heavy box. The force of gravity pulls it downwards with a force of 400 N. Your father applies an upward force of 170 N from below. How much force will you have to apply to lift it upwards?
(a) 220 N
(b) 230 N
(c) 300 N
(d) less than 220 N

Q. Which of the following has more inertia? A ₹ 10 coin and a ₹ 1 coin.

Q.

Is absolute motion possible in nature?

Q.

A body of mass $2kg$ is moving with an acceleration of $10m/s^2$. The net force acting on the body is

1. $10N$

2. $20N$

3. $50N$

4. $260N$

Q.

If we know the magnitude of net force acting on a body of a given mass which is initially at rest, with the help of Newton's second law, we can determine its:

1. inertia

2. momentum

3. velocity

4. acceleration

Q.

Question 16

A gas filled balloon moves up. Is the upward force acting on it larger or smaller than the force of gravity?

Q.

If the total momentum of a system is changing, then

1. The particles of system must exert force on each other

2. The system must be under the influence of gravity

3. A net external force must act on the system

4. None of the above

Q. An object moves with an acceleration of $3m{s}^{-2}$ when a force of $30N$ is applied. Find the mass of the body.

1. $20kg$
2. $30kg$
3. $10kg$
4. $40kg$

Q. If momentum of an object is increased by 10% then its kinetic energy will increase by 1. 20% 2. 21% 3. 40% 4. 10%

Q. The pull or push experienced by an object is known as force.

1. True
2. False

Q.

If mass and radius of the Earth are $6.0\times {10}^{24}$ kg and $6.4\times {10}^6$ m respectively, calculate the force exerted by the Earth on a body of mass 1 kg. Also, calculate acceleration produced in the body of mass 1 kg and acceleration produced in the Earth.

1. and 9.8 respectively

2. 9.8 for both

3. 9.8 and 1 respectively

4. 9.8 and respectively

Q. Friction does not depend on the nature of the surfaces that are in contact with each other.

1. True
2. False

Q. When you a body, it moves away from you.

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

Q. A $20kg$ body is moving with a velocity of $7.5m{s}^{-1}$. What is the force required to make it come to rest in three seconds.

1. $45N$
2. $50N$
3. $55N$
4. $50N$

Q. What do you understand by states of motion of an object?

Q. According to Newton’s second law, force applied is proportional to:

1. momentum
2. rate of change of momentum
3. velocity
4. inertia

Q. A force causes a $10kg$ body to double it’s velocity in four seconds. If the final velocity of the body is $7.2m{s}^{-1}$, calculate the magnitude of the force.

1. $9N$
2. $8.6N$
3. $12.4N$
4. $6.8N$

Q. Mass times the rate of change of velocity of an object is equal to:

1. Speed
2. Momentum
3. Force
4. Displacement

Q.

What force will change the velocity of an object of mass $2.5Kg$ from $5m{s}^{-1}$ to $10m{s}^{-1}$ in 5 seconds?

1. 2.5 N

2. 5 N

3. 10 N

4. 7.5 N

Q. a block of mass m is placed on a horizontal surface. If the block is pulled by applying a force of magnitude $F=5mg$ at an angle $\theta ={37}^0$ with horizontal as shown in $Fig.6.29$, find the acceleration of the block at the given instant.

Q. The equations of motion are developed for objects having constant acceleration and undergoing one dimensional motion.

1. False
2. True

Q. The SI unit of force is​

1. Pa
2. N
3. m
4. kg

Q. Give Reasons for the following:
Why is it difficult to balance our body when we accidentally step on the peel of banana ?

Q.

What Force should be applied on an object of mass 50kg .to make it accelerate upto50 kg /hr

Q. A force makes a stationary body of mass $25kg$ to move $60m$ in $10s$. Find the magnitude of this force.

1. $25N$
2. $30N$
3. $35N$
4. $40N$