M.C.Q : Kinematics ( 1 to 1 0 )

LEVEL – I

1. A stone is released from an elevator going up with acceleration 5 m/s2 . The acceleration of the stone after the release is:

(A) 5 ms-2

(B) 4.8 ms-2 upward

(C) 4.8 down ward

(D) 9.8 ms-2 down ward

2. The locus of a projectile relative to another projectile is a

(A) straight line

(B) circle

(C ) ellipse

(D) parabola

3. A car accelerates from rest at constant rate of 2 m/s2 for some time. Then its retards at a constant rate of 4 m/s2 and comes to rest. What is the maximum speed attained by the car if it remains in motion for 3 seconds

(A) 2 m/s

(B) 3 m/s

(C) 4 m/s

(D) 6 m/s

4. The co-ordinates of a moving particle at any time t are given by x = ct2 and y = bt2. The speed of the particle is given by:

(A) 2t (c + b)

(B) 2t√(c2-b2)

(C) t√(c2-b2)

(D) 2t√(c2-b2)

5. A particle parallel to x-axis as shown in the figure such that at all instant the y axis component of its position vector is constant and is equal to ‘b’. The angular velocity of the particle about the origin is
mcq kinematics

(A) v/b

(B) (v/b)Sinθ

(C) (v/b) Sin2θ

(D) vb

6. A particle is projected vertically upwards and it attains maximum height H. If the ratio of times to attain height h(h < H) is 1/3, then h equals

(A) 2/3. H

(B) 3/ 4. H

(C) 4/3 . H

(D) 3/2. H

7. A boy B drags a wedge A by an in extensible string passing over the pulleys 1,2,3 & 4 as shown in the figure . If all the pulleys are smooth and the boy walks with constant velocity of magnitude v, the magnitude of relative velocity between the boy and the wedge is equal to

(A) v

(B) 2v

(C) 1.5v

(D) 1.25v

8. A swimmer wishes to reach directly opposite bank of a river, flowing with velocity 8 m/s. The swimmer can swim 10 m/s in still water. The width of the river is 480 m. Time taken by him to do so:

(A) 60 sec

(B) 48 sec

(C) 80 sec

(D) None of these

9. A man can swim at a speed of 5 km/h w.r.t. water. He wants to cross a 1.5 km wide river flowing at 3 km/h. He keeps himself always at an angle of 60° with the flow direction while swimming. The time taken by him to cross the river will be

(A) 0.25 hr.

(B) 0.35 hr.

(C) 0.45 hr.

(D) 0.55 hr.

10. A disc of radius R is rotating inside a room A boy standing near the rim of the disc, finds the water droplets falling from the ceiling is always hitting on his head. As one drop hits his head the next one starts from the ceiling. If height of the roof above his head is H. Angular velocity of disc is:

(A)

B)

(C)

(D)

ANSWER:

1.(D)   2. (A)   3. (C)   4. (D)  5. (C)   6. (C)   7. (D)   8. (C)  9. (B)   10. (C) 

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