Momentum

Q.

Important formulas in the chapter force and laws of motion.

Q.

Explain what is momentum?

Q.

If no external forces acts on a system of particles then the momentum of the system remains conserved.

1. True

2. False

Q.

Define Momentum. Write its SI unit.

Q.

How much momentum will a dumbbell of mass $10kg$ transfer to the floor if it falls from a height of $80cm$? Take its downward acceleration to be $10m{s}^{-2}$.

Q.

Is momentum a scalar or vector?

Q.

A particle of mass m is projected with a velocity v making an angle 45 degree with the horizontal. The magnitude of the angular momentum of the projectile about the pointof projection when the particle is at its max height h.

Q.

A balloon is at a height of 81m and is ascending upwards with a velocity of 12 m/s. A body of 2kg weight is dropped from it. If $g=10m{s}^{-2}$ the body will reach the surface of the earth in how much time?

Q.

A cricket ball is dropped from a height of 20 m. Calculate the speed of the Ball when it hits the ground and calculate the time it takes to fall through this height. ($g=10m{s}^{-2}$)

Q.

Lugage placed on the roof of a car or bus is tied with rope.Give reason.

Q.

If two bodies of different masses have the same K.E. then the relation between momentum and mass will be:

1. 

2. 

3. 

4. 

Q.

A hockey ball of mass 200 gram travelling at 10 m/s is struck by a hockey stick so as to return it along with original path with a velocity at 5 m/s . Calculate the change of momentum Orchid in the motion of the hockey Ball by the force applied by the hockey stick.

How did the change of momentum have postive sign?

Q.

How much momentum will a dumbbell of mass $10kg$ transfer to the floor if it falls from a height of $80cm$ (assume that the dumbbell stops after hitting the ground, g=$10m{s}^{-2}$)?

1. 40 kg m/s

2. 50 kg m/s

3. 30 kg m/s

4. 35 kg m/s

Q.

Two bodies of masses $m_1$and $m_2$ have equal kinetic energies. What is the ratio of their linear momenta?

Q.

What is the momentum of an object of mass m, moving with a velocity v?

1. ${\left(\mathrm{mv}\right)}^2$

2. ${\mathrm{mv}}^2$

3. $\frac{1}{2}{\mathrm{mv}}^2$

4. $\mathrm{mv}$

Q.

Explain why it is dangerous to jump from a moving bus

Q.

Two bodies of masses $m_1$ and $m_2\left(>m_1\right)$ have equal linear momentum. Which body possesses greater kinetic energy?

Q. The masses of two bodies are in the ratio 5 : 6 and their velocities are in the ratio 1 : 2. Then their linear momentum will be in the ratio

1. 5 : 6
2. 1 : 2
3. 12 : 5
4. 5 : 12

Q.

A body of mass 5 kg is moving with velocity $2m{s}^{-1}.$ Calculate its linear momentum.

Q.

What is another name for a change in momentum?

Q.

A body of mass $4kg$ is accelerated up by a constant force, travels a distance of $5m$ in the first second and a distance of $2m$ in the third second. The force acting on the body is

1. $2N$

2. $4N$

3. $6N$

4. $8N$

Q.

Two balls A and B of masses m and 2m are in motion with velocities 2v and v respectively. Compare : (i) their inertia, (ii) their momentum, and (iii) the force needed to stop them in the same time.

Q.

What is the momentum of a 6 kg ball bowling with a velocity of 2.2 metre per second square

Q. Why p=mv . why it can't be anything else like mv2, m+v etc.

Q.

A bullet of mass 50 g moving with an initial velocity of 100 m $s^{-1}$ strikes a wooden block and comes to rest after penetrating a distance 2 cm in it. Calculate
(i) initial momentum of the bullet,
(ii) final momentum of the bullet,
(iii) retardation caused by the wooden block, and
(iv) resistive force exerted by the wooden block

Q.

Newton's laws of motion are applicable to which frame?

1. Non-inertial frame of reference.

2. Laws of motions are frame independent.

3. Inertial frame of reference.

4. None of the above.

Q.

A lead bullet of mass $2kg$, traveling with a velocity of $20m·s^{-1}$, comes to rest after penetrating $20m$ in a still target. Find the resistive force applied by the target and acceleration of the bullet.

Q.

A ball of mass 0.1 kg is thrown against a wall... It strikes the wall normally with a velocity of 30 m/s and rebounds with a velocity of 20 m/s. Calculate the change in momentum of the ball...

Q.

Two bodies of masses 1 kg and 4 kg have equal linear momentum. What is the ratio of their kinetic energies?

Q.

A bullet of mass A and velocity B is fired into a wooden block of mass C. If the bullet gets embedded in the wooden block, then the the magnitude of velocity of the system just after collision will be

(a)A+B/AC . (b)A+C/B+C . (c)AC/B+C . (d)AB/A+C