Conservation of Momentum

Q. A stone is dropped from a height h .It hits the ground withba certain momentum P .If the same stone is dropped from a height 100% more than the previous height, the momentum when it hits the ground will change by -68% -41% -100% -200

Q. A body is falling from height h it takes 8s to reach the ground .the time it takes to cover the first one fourth of height is?

Q. 27.A body mass 5kg is acted upon by two perpendicular forces 8n and 6n give the magnitude and direction of the acceleration of the body

Q. A body dropped from height h with initial velocity zero, strikes the ground with a velocity 3m/s. Anothr body of same mass is thrown from the same height h with an initial velocity of 4 m/s. Find the final velocity of second mass, with which it strikes the ground 1)5m/s 2) 3m/s

Q.

A 100 g iron ball having velocity 10 m/s collides with a wall at an angle ${30}^o$ and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is

1. 10 N

2. 100 N

3. 1.0 N

4. 0.1 N

Q. 29. A particle start moving from rest state along astraight line under the action of a constant forceand travel distance x in first 5 seconds. Thedistance travelled by it in next five seconds will be(2) 2x37.(4) 4x(3) 3x

Q. 74. A body of mass m falls from height h on ground. If e be the coefficient of restitution of collision between the body and the ground, then the distance travelled by body before it comes to rest is?

Q. A block of weight W is supported by three strings as shown in figure. Which of the following relations is true for tension in the strings? (Here T1, T2 and T3 are the tension in the strings A, B and C respectively

Q. if n balls hit elastically and normally on a surface per unit time and all balls of mass m are moving with same velocity u, then force on surface is: (WHY CANT WE USE "F=nmv" HERE?)

Q.

A rifle bullet loses $1/{20}^{th}$ of its velocity in passing through a plank. The least number of such planks required just to stop the bullet is

1. 5

2. 10

3. 11

4. 20

Q.

A ball of mass 4 kg moving with a velocity of 12 m/s impinges directly on another ball of mass 8 kg moving with velocity of 4 m/s in the same direction. Find their velocities after impact (if $e$ = 0.5)

1. 2 m/s, 4 m/s

2. 4 m/s, 8 m/s

3. 4 m/s, 6 m/s

4. 4 m/s, 12 m/s

Q. A spacecraft of mass M explodes into two parts when its velocity is V. After the explosion, one part of mass m is left stationary. What is the velocity of the other part?

1. 
2. 
3. 
4. 

Q. 42. A rocket of mass 2000 kg is ejecting the gasses at the rate of 50 kg/sec with speed of 20 m/sec in gravity free space. Find the acceleration of rocket at 2 sec.

Q. A ball of mass 20 g dropped over a large horizontal surface from a height of 5 m, collides elatically with the surface. If the collision lasts for 10^{-2} s, which of the following statement is true? (g=10 m/s^2) (1) The impulse imparted to the ball is 0.4 n-s (2) Force applied by the ball on the flower is 50 N (3) The impulse imparted to the ball is 0.2 N-s (4) Force exerted by the surface on the ball is 0.2 N

Q. In meldes experiment when tension in the string is 12gwt 4 loops are obtained calculate tension in the string to form 3 loops if all other conditions are remaining the same

Q. two bodies of mass in the ratio 1:2 fall from heights in the ratio 3:4 .the ratio of their linear momentum on reaching the ground will be

Q. 74.two masses m1 and m2 are connected by a massless string find the value of tension in the spring if a force of 200N is applied on (i)m1 and (ii)m2

Q. A body of mass m falls from height h on ground. If e be the coefficient of restitution of collision between the body and ground, then the distance travelled by body before it comes to rest is,

Q. A molecule of mass m of an ideal gas collides with the wall of the vessel with the velocity v and returns back with the same velocity. The change in the linear momentum of the molecule will be

Q. A trolley of mass 200 kg moves with a uniform speed of 36 km/h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of 4 m s–1 relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. What is the final speed of the trolley ? How much has the trolley moved from the time the child begins to run ?

Q. Abatsmen deflects a ball by an angle of90^0.wihout changing its initial speed , which is equal to 54 km/ hr.What is impulse imparted to the ball? ( mass of ball is 0.15kg

Q.

A block of mass $m$ moving at a velocity $v$ collides head on with another block of mass $2m$ at rest. If the coefficient of restitution is $\frac{1}{2}$, find the velocities of the blocks after the collision.

1. 

2. 

3. 

4. 

Q. 6.A Ball of mass 1kg dropped from 9.8 m height , strikes the ground and rebound to a height of 4.9 m . If the time of contact between Ball and ground is 0.1 s, then find impulse and average force acting on ball

Q. A perfectly straight portion of a uniform rope has mass M and length L. At end A of the segment, the tension in the rope is Ta and at B it is Tb (Tb>Ta). Neglect effect of gravity and no contact force acts on the rope in between points A and B. The tension in the rope at distance L/5 from end A is:

Q. 32. A rod of mass M and length L is suspended with the help of 2 light strings A and B as shown in the figure. Find the tension in string A

Q. 92. In figure a heavy ball of mass 2m rests on the horizontal surface and the lighter ball of mass m is dropped from a height h >2l. At the instant the string gets taught, the upward velocity of the heavy ball will be?

Q.

A wagon weighing 1000 kg is moving with a velocity 50km/h on smooth horizontal rails. A mass of 250 kg is dropped into it. The velocity with which it moves now is

1. 2.5 km/hour

2. 20 km/hour

3. 40 km/hour

4. 50 km/hour

Q.

A bomb of mass 16kg at rest, explodes into two pieces of masses 4kg and 12kg. After explosion, the velocity of the 12kg mass is 4m/s. What is the velocity of the 4kg piece?

1. -4 m/s

2. -12 m/s

3. 12 m/s

Q. A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m s¯¹, what is the recoil speed of the gun ?

Q. A bomb of mass $2\text{kg}$ at rest explodes into two chunks of masses $0.5\text{kg}$ and $1.5\text{kg}$. Velocity of $0.5\text{kg}$ chunk is ($2\hat{i}+4\hat{j}+8\hat{k}$) $\text{m/s}$. Velocity of $1.5\text{kg}$ chunk is -

1. $(\frac{2}{3}\hat{i}+\frac{4}{3}\hat{j}+\frac{8}{3}\hat{k})$ $\text{m/s}$
2. $-(\frac{2}{3}\hat{i}+\frac{4}{3}\hat{j}+\frac{8}{3}\hat{k})$ $\text{m/s}$
3. $(\frac{2}{3}\hat{i}-\frac{4}{3}\hat{j}+\frac{8}{3}\hat{k})$ $\text{m/s}$
4. $(\frac{2}{3}\hat{i}-\frac{4}{3}\hat{j}-\frac{8}{3}\hat{k})$ $\text{m/s}$