# Momentum

## Trending Questions

**Q.**

If the momentum of an object is increased by 10% then its kinetic energy will increase by?

**Q.**

What happens to kinetic energy when momentum is doubled?

**Q.**

A bullet of mass $5g$, travelling with a speed of $210m/s$, strikes a fixed wooden target. One half of its kinetic energy is converted into heat in the bullet while the other half is converted into heat in the wood. The rise of temperature of the bullet if the specific heat of its material is $0.03cal/gm\xb0C$ ($1cal=4.2\times {10}^{7}ergs$) close to:

$38.4\xb0C$

$87.5\xb0C$

$83.3\xb0C$

$119.2\xb0C$

**Q.**

A bomb of mass $9kg$ explodes into two parts. One part of mass $3kg$ moves with velocity $16m/s$, then the kinetic energy of the other part is

$162J$

$150J$

$192J$

$200J$

**Q.**

When a bullet is fired at a target, its velocity decreases by half after penetrating $30cm$ into it. The additional thickness it will penetrate before coming to rest is

$30cm$

$40cm$

$10cm$

$50cm$

**Q.**A particle of mass M is moving in a horizontal circle of radius R with uniform speed V. When it moves from one point to a diametrically opposite point, its

- Kinetic energy changes by MV24
- momentum does not change.
- Momentum changes by 2MV.
- Kinetic energy changes by MV2

**Q.**

A particle is moving in a horizontal circle with a constant speed. Which of the following remains constant?

Kinetic energy of the body

Momentum of the body

Radial acceleration

Displacement of the body from the center of the circle

**Q.**

A bomb is $12kg$ and divides into two parts whose ratio of masses is $1:3$. If the kinetic energy of a smaller part is $216J$, then the momentum of a bigger part in $kg-m/sec$ will be

$36$

$72$

$108$

Data is incomplete

**Q.**A man throws balls with the same speed vertically upwards one after the other at an interval of 2 seconds. What should be the speed of the throw so that more than two balls are in the air at any time (Given g=9.8m/s2

^{ )}

- Only with speed 19.6 m/s
- At least 0.8 m/s
- Any speed less than 19.6 m/s
- More than 19.6 m/s

**Q.**A tunnel is dug across the earth of mass M and radius R at a distance R/2 from the centre O of the Earth as shown. A body is released from rest from one end of the smooth tunnel. The velocity acquired by the body when it reaches the centre C of the tunnel is

- √3GM2R
- √3GM4R
- √3GM8R
- √3GM16R

**Q.**

A body of mass ${10}^{-2}kg$ is moving in a medium and experiences a frictional force $-k{v}^{2}$. Its initial speed is ${v}_{0}=10m{s}^{-1}$. If, after time $10s$, its energy is $\frac{1}{8}m{v}_{0}^{2}$, the value of $k$ will be:

${10}^{-3}kg{m}^{-1}$

${10}^{-3}kg{s}^{-1}$

${10}^{-4}kg{m}^{-1}$

${10}^{-1}kg{m}^{-1}{s}^{-1}$

**Q.**A rod of length L has non-uniform linear mass density given by ρ(x)=a+b(aL)2, where a and b are constants and 0≤x≤L. The value of x for the centre of mass of the rod is at:

- 32(a+b2a+b)L
- 34(2a+b3a+b)L
- 43(a+b2a+3b)L
- 32(2a+b3a+b)L

**Q.**On a planet a freely falling body takes 2 sec when it is dropped from a height of 8 m, the time period of simple pendulum of length 1 m on that planet is

**Q.**A lead ball strikes a wall and falls down while a tennis ball having the same mass and velocity strikes the wall and bounces back. Check the correct statement.

- The momentum of the lead ball is greater than that of the tennis ball.
- The lead ball suffers a greater change in momentum compared with the tennis ball.
- The tennis ball suffers a greater change in momentum as compared with the lead ball.
- Both suffer an equal change in momentum.

**Q.**Two masses m1 and m2 are connected by a massless spring of constant k and unstretched length L. The masses are placed on a frictionless straight channel, which is considered as x -axis. They are initially at rest at x=0 and x=L respectively. At t=0, a velocity of v0 is suddenly imparted to the first particle. At a later time t0, the centre of mass of the two masses is at x=

- m2Lm1+m2
- m1Lm1+m2+m2v0tm1+m2
- m2Lm1+m2+m1v0tm1+m2
- m2Lm1+m2+m2v0tm1+m2

**Q.**A- if m and mo are moving mas , rest mass of body and c is velocity of light then kinetic energy of body is E=[m-m0]c2 R-total energy of body is sum of kinetic energy and rest mass energy

**Q.**The ratio of radii of nuclei 13Al27 and 52XP is 3:5. The number of neutrons in the nuclei of X will be

**Q.**The kinetic energy k of a particle moving along a circle of radius R depends on the distance covered s as k=as2 where a is a constant. The force acting on the particle is

**Q.**

Three particles of mass m each are placed at the three corners of an equilateral triangle of side a. Find the work wihch should be done on this system to increase th esides of the triangle to 2a.

**Q.**Figure shows the variation of force acting on a body with time. Assuming the body to start from rest the variation of its momentum with time is best represented by which plot?

**Q.**

A gun of mass $M$ fires a bullet of mass $m$ with maximum speed $v$. Given that $m<M$ what is the kinetic energy of the gun?

**Q.**If the absorptive power of a surface is 0.6 then the energy incident if the energy reflected is 70 J is -

Assume transmissivity is zero.

- 175 J
- 165 J
- 155 J
- 145 J

**Q.**An object of mass 10 kg is moving at a speed 4 metre per second. What is the kinetic energy of the object?

**Q.**

A body of mass m makes an elastic collision with another identical body at rest.Show that if the collision is not head-on, the bodies go at right angle to each other after the collision.

**Q.**

Two particles A and B of mass of 10 g and 20 g respectively fall vertically. At a given time, the speed of particle A is 12 m/s and that of B is 15 m/s. Find the total linear momentum of the system of the two particles.

**Q.**From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 ms−1. Calculate the initial recoil velocity of the rifle.

**Q.**

A bullet of mass 20 g is fired horizontally with a velocity of 100 m/s from a pistol of mass 1.5 kg. Calculate the recoil velocity of the pistol.

**Q.**

A particle of mass$m$ is dropped from a height $h$ above the ground. At the same time another particle of the same mass is thrown vertically upwards from the ground with a speed of $\sqrt{2gh}$. If they collide head on completely in elastically, the time taken for the combined mass to reach the ground, in units of $\sqrt{\frac{h}{g}}$ is:

$\sqrt{\frac{3}{2}}$

$\sqrt{\frac{1}{2}}$

$\frac{1}{2}$

$\sqrt{\frac{3}{4}}$

**Q.**Six bullets of mass 5 gm are fired from a gun of mass 5 kg. What is the speed of the gun if the speed of the bullets w.r.t. the ground is 200 m/s?

- 1.2 m/s
- 0.2 m/s
- 200 m/s
- 2006 m/s

**Q.**A projectile of mass 4M is fired at a speed of 100 m/s at an angle of 37∘ from the horizontal. At the highest point, the projectile breaks into two parts with mass M and 3M. Mass M falls down immediately after the explosion and mass 3M lands at some horizontal distance from mass M. Choose the correct statement. (Take g=10 m/s2)

- None of the above
- Time taken by 4M to reach the highest point and time taken by 3M to land on the ground from the highest point will be the same.
- Time taken by 4M to reach the highest point and time taken by 3M to land on the ground from the highest point will be different.
- Distance covered by 4M along the horizontal ground and distance covered by 3M along the horizontal ground will be the same.