Q. 6. The instantaneous angular position of a point on a rotating wheel is given by the equation The torque on the wheel becomes zero at
(1) t = 2 s (2) t = 1 s
(3) t = 0.2 s (4) t = 0.25 s
Sol:
Answer : (2)
Q. 7. A particle moves in a circle of radius 5 cm with constant speed and time period 0.2 π s. The acceleration of the particle is
(1) 5 m/s2 (2) 15 m/s2
(3) 25 m/s2 (4) 36 m/s2
Sol:
Answer : (1)
Q.8. A body of mass M hits normally a rigid wall with velocity V and bounces back with the same velocity. The Impulse experienced by the body is
(1) Zero (2) MV
(3) 1.5 MV (4) 2 MV
Sol.
Impulse = MV – (– MV) = 2 MV
Answer: (4)
Q.9 . A planet moving along an elliptical orbit is closest to the sun at a distance r1 and farthest away at a distance of r2. If v1 and v2 are the linear velocities at these points respectively. Then the ratio v1/ v2
Sol.
Answer (3)
Q.10. A radioactive nucleus of mass M emits a photon of frequency n and the nucleus recoils. The recoil energy will be
Sol.
Answer (3)