# NCERT Physics Class 11 Exemplar Ch 4 Motion in A Plane Part 2

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## MCQ II

11 Two particles are projected in air with speed at angles and (both acute) to the horizontal, respectively. If the height reached by the first particle is greater than that of the second, then tick the right choices

(a) Angle of projection:

(b) Time of flight:

(c) Horizontal range:

(d) Total energy:

Ans: (a), (b)

12 A particle slides down a frictionless parabolic track starting from rest at point A. Point B is at the vertex of parabola and point C is at a height less than that of point A. After C, the particle moves freely in air as a projectile. If the particle reaches highest point at P, then

(a) KE at at B

(b) Height at P = height at A

(c) Total energy at P = total energy at A

(d) Time of travel from A to B = time of travel from B to P.

Ans: (c)

13 Following are four different relations about displacement, velocity and acceleration for the motion of a particle in general. Choose the incorrect one (s):

(a)

(b)

(c)

(d)

Ans: (a), (c)

14 For a particle performing uniform circular motion, choose the correct statement(s) from the following:

(a) Magnitude of particle velocity (speed) remains constant.

(b) Particle velocity remains directed perpendicular to radius vector.

(c) Direction of acceleration keeps changing as particle moves.

(d) Angular momentum is constant in magnitude but direction keeps changing

Ans: (a), (b), (c)

15 For two vectors A and B is always true when

(a)

(b)

(c) and A and B are parallel or anti-parallel

(d) When either or is zero.

Ans: (b), (d)