Question

1. A particle undergoing circular motion in the xy-plane stops on the negative x-axis. Which of
the following does not describe the angular position?
a) 4π radians
b) π radians
c) 5π radians
d) 3π radians
2. Two balls collide. The first ball (mass 3 kg) reaches a speed of 40 m/s before the collision.
After the collision, the first ball has stopped and the second ball (mass 3 kg) travels at 40 m/s.
What was the initial velocity of the second ball?
a) -13.33 m/s
b) 40 m/s
c) 13.33 m/s
d) 0 m/s
3. Which of the following is not conserved in a collision where two cars bounce off each other
and move at different velocities?
a) momentum
b) energy
c) impulse
d) none of the above
e) all of the above
4. What type of collision is two billiard balls colliding, where they bounce off each other and
move at equal and opposite velocities?
a) Elastic
b) Inelastic
c) Perfectly inelastic
d) Perfectly elastic

Answer 1

1.

when a particle stops on the -ve x axis which is pi radians

among the given options 4pi radians is not describing the angular position

along +y direction pi/2 radians

along -x axis 2pi/2 radians = pi radians = 3pi radians = 5 pi radians

along -y direction 3pi/2 radians

along +x direction 4pi/2 radians = 2pi radisna = 4pi radians

answer is option A

2.

m1 = 3 kg = m2

u1 = 40 m/s , v1 = 0 m/s

u2 =? , v2 = 40 m/s

from conservation of momentum  

m1*u1+m2*u2 = m1*v1+m2*v2

substituting the values

3*40 + 3*u2 = 3*0+3*40

solving for u2 , u2 = 0 m/s

so the initial velocity of th second ball is 0 m/s, that is it is at rest

3. if two cars are collided and bounce of each other , only momentum will conserved other are not conserved  

in inelastic collision , only momentum conserved , kinetic energy will not xconserved and the impulse also

4.

here the collision of two billiard balls they bounce of each other and move equal and opposite velocities s

the conservation of momentum and kinetic energy also conserved

so the collision is elastic collision