NCERT Physics Class 11 Exemplar Ch 4 Motion in a Plane Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

Doorsteptutor material for NCO Class-11 is prepared by world's top subject experts: fully solved questions with step-by-step explanation- practice your way to success.


16 A cyclist starts from centre O of a circular park of radius 1km and moves along the path OPRQO as shown. If he maintains constant speed of , what is his acceleration at point R in magnitude and direction?

A Cyclist Circular Park of Radius

Ans: 16.

  • in the direction RO.

17 A particle is projected in air at some angle to the horizontal, moves along parabola as shown in Fig. 4, where x and y indicate horizontal and vertical directions, respectively. Show in the diagram, direction of velocity and acceleration at points A, B and C.

Horizontal and Vertical Direction Respectively


  • The students may discuss with their teachers and find answer.

18 A ball is thrown from a roof top at an angle of above the horizontal. It hits the ground a few seconds later. At what point during its motion, does the ball have

(a) Greatest speed.

(b) Smallest speed.

(c) Greatest acceleration? Explain


(a) Just before it hits the ground.

(b) At the highest point reached.

(c) constant.

19 A football is kicked into the air vertically upwards. What is its (a) acceleration, and (b) velocity at the highest point?


  • Acceleration .
  • Velocity .

20 A, B and C are three non-collinear, non-co-planar vectors. What can you say about direction of ?


  • Since is perpendicular to plane of B and C, cross product of any vector will lie in the plane of B and C.