A ball of mass m and velocity v strikes a wall at right angles and rebounds with undiminished speed. During the time t of collision, average force exerted on the wall is
mv2/2
mv2/t
mv2/2t
2mv/t
A bomb of mass 20 kg explodes into two pieces of mass 5 kg and 15 kg. If velocity of first part is 300 m/s, the velocity of other part would be
zero
30 m/s
100 m/s
900 m/s
A bullet of mass m1 and moving with velocity v1 strikes a wooden block of mass m2 lying on a frictionless surface and gets embedded into it. The final velocity of the system is
(m1 + m2) v1
m1/m1 + m2 v1
m1 + m2/m1 v1
m1/(m1 + m2) v1
A body of mass m moving with a constant velocity v hits another body of the same mass moving with the same velocity but in the opposite direction and sticks to it. After this collision, the composite system will move with a velocity
zero
v/2
v
2v
A body of mass m moving towards right with a constant velocity v hits another body of twice the mass moving towards left with half the velocity. If they stick together on collision, they will
come to rest
move towards right
move towards left
can come to rest or move in any direction depending upon magnitude of masses and their velocities
The weight of a pile driver is 250 kg and it drops freely 10 m on the top of a pile weighing 1000 kg. If the pile is driven by 10 cm, the common velocity of the pile driver and the pile after the impact is
(Take g= 9.8 m/s2.)
1.4 m/s
2.8 m/s
3.5 m/s
4.2 m/s
A body of mass m moving with velocity v makes a head-on elastic collision with a stationary body of mass nm. The fraction of the incident energy transferred to the body at rest is
n/n+1
n/(n+1)2
2n/(n+1)2
4n/(n+1)2
Consider a one-dimensional elastic collision between an incoming body A of mass m1 and a body B of mass m2 initially at rest. For body B to move with greatest kinetic energy after collision
m1>m2
m1 m1 = m2
body A should recoil after collision
A particle of mass 4m which is at rest explodes into three fragments. Two of the fragments and each of mass m are found to move with a speed v, each in mutually perpendicular directions. The total energy released in the process of explosion is
mv2
3/2 mv2
m2
4 mv2
A 0.125 kg plastic ball collides head on with a 0.5 kg lead ball whose speed is three times that of plastic ball. At the instant of contact, the ratio of the magnitudes of force on the plastic ball, and that on the lead ball will be
1 : 1
3 : 1
4 : 1
12 : 1