21.  Rohit completes a semi circular path of radius R in 10 seconds. Calculate average speed and average velocity in m/s.

22.  A particle moves 4m in the south direction. Then it moves 3m in the west direction. The time taken by the particle is 2 second. What is the ratio between average speed and average velocity ?

23.  A particle is projected vertically upwards with velocity 30 m/s. Find the ratio of average speed and instantaneous velocity after 6 s.

24.  The motion of a particle along a straight line is described by the function . Calculate the acceleration after 10s.

26.  A body starts its motion with zero velocity and its acceleration is . Find the distance traveled by it in fifth second.

27.  A body is moving in x direction with constant acceleration . Find the difference of the displacement covered by it in nth second and second.

28.  What does the speedometer measure kept in motorbike ?

29.  The displacement of a particle in x direction is given by . Find the velocity at time

30.  A freely falling particle covers a building of 45m height in one second. Find the height of the point from where the particle was released.