6. To a ground observer the block C is moving with v, and the block A with v. B is moving with v relative to C as shown in the figure. Identify the correct statement. (a) V-V =Vo (b)= A C B (c) V+V = V (d) None of these 7. A particle free to move along x-axis is acted upon by a force F=-ax+bx where a and b are positive constants. For x0, the correct variation of potential energy function U(x) is best represented by (take U(0) = 0). (a) 8. 9. UA (b) UA 04 Ax In system of particles, internal forces can change: (a) The linear momentum but not the kinetic energy (b) The kinetic energy but not the linear momentum (c) Linear momentum as well as kinetic energy (d) Neither the linear momentum nor the kinetic energy p (d) From a point on smooth floor of a room, a ball is shot to hit a wall. The ball then returns back to the point of projection. If the time taken by the ball in returning is twice the time taken in reaching the wall, find the coefficient of restitution. (a) e = (b) e = (c) e = (d) e=0.2 10. A ball is projected horizontal with a velocity of 5ms from the top of a building 20m Displacement of ball when it hits the ground is : (g = 10m/s) (a) 10 m (b) 20 m (c) 103m (d) 105m