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Objective Problems, { Level 1 |, , Kinematics of Circular Motic, , , , , , , , , , 1. A particle is moving on a eiteular path of 10 m radius, AC, any instant of time its speed is $ vs and the speed is, increasing at a tate of 2 nvs?, At this instant the, magnitude of the net acceleration will be, @ 32m? () 24?, , (©) 25 ms (@) 43 ws, 2. Ina typical projectile motion tangential acceleration at, the topmost point P of the trajectory is, ¥ (vera), | £x, VA, "x {Horizontal), @s (©) g cos, 0 (@) None of these, , 3. A point on the rim of a flywheel has a peripheral speed of, 10-mis at an instant when it is decreasing at the rate of, 60 m/s*. Ifthe magnitude of the total acceleration of the, point at this instant is 100 m/s*, the radius of the flywheel, is, (@) 125m, (©) 25m, , ©) 25m, (@) 25m, 4. A panicle is moving on a circular track of radius 30 em, ‘with a constant speed of 6 m/s Its acceleration is, (a) 2210 (b) 120 mis?, © 1.2 mss? (@) 36 mis?, 5. In case of a uniform circular motion, velocity and, acceleration are, , (a) perpendicular, (©) in opposite direction, , (b) in same direction, (4) not related to each other, , , , G.Let a, and a, represent radial and tangential, accelerations. The motion of a particle may be circular, if, @) a= (b) a, =0,0,20, (©) 4, 40, (@) None of these, , , , 7. The speed of a particle moving in a circle is increasing,, The dot product ofits acceleration and velocity is, (a) negative, () zer0, (©) positive, (A) may be positive or negative, , , , 8. The ato of angular speeds of minute hand and hry, of a wate i, @ ie () 61, (124 (a) 1:6, , 9. The angular speed of a flywheel making 120 rev/min, (a) 2n rad/s (©) 4x? rad/s, (6) mrad (@) An rad/s, , 10. A particle moves with constant speed v along a cia, , , , path of radius r and completes the circle in time 7. 1,, acceleration of the particle is, 2 2nr, (a) 2 =, wo a, o 7 =, m, , 11. A body is moving in a circular path with acceleration, its speed gets doubled, find the ratio of acceleration af,, and before the speed is changed, @is4 () 1:2, 2:1 (@) 4:1, , 12. The circular orbit of two satellites have radii rand,, respectively (r, <r; } Ifangular velocities of satellites ar, same, then their centripetal accelerations are related as, (0) a> a ©) a, =a,, , (©) a, <a, (@) Data insufficient, , 13. The wheel of a toy car rotates about a fixed axis. Itslows, * down from 400 rps to 200 rps in 2 s. Then, its anguls, retardation in rad/s is (rps = revolutions per second), (@) 200% (b) 100, (©) 400n (€) None of these, , 14. A caris circulating on a circular path of radius r. Atsomé, instant its velocity is vand rate of increase of speed is, The resultant acceleration of the car will be, , paul 2, fe, , () J +a, , @ (¢ + 4), , , , 15. A point stars from rest and moves along a circular, with a constant tangential acceleration. After, rotation, the ratio of its radial acceleration 10, tangential acceleration will be equal to, f@t (b) 2x, , 1, oo (d) 4x