Modified True or False. Write the correct answer if false.

1. Friction is proportional to the normal force and is directed parallel to the surface.

2. The net force acting on a particle equals the change of moment of the particle with respect to experience.

3. The study of kinematics of particle deals with displacement, velocity, acceleration and force. 4. If acceleration-time diagram is represented by a horizontal straight line then displacement is a cubic curve.

5. The potential energy of a particle is equal to. 6.When a particle moves under the action of conservative forces, the sum of the kinetic energy and of the gravitational potential energy of the particle remains constant.

7. The net force acting on a particle equals the change of moment of the particle with respect to experience

8. Coefficient of restitution is the ratio of the impulse at the period of deformation to the impulse at the period of restitution.

9.In oblique central impact, the motion of the particles is not directed along the line of impact.