218. A projectile is fired with a velocity of 100.3 in/sec. at an elevation of 60?. The velocity attained by the projectile when it is moving at a height of 100 m, is

A. 70 in/sec.

B. 75 m/sec. (c) 80 m/sec.

C. 85 m/sec.

D. 90 m/sec.

219. One end of a light string 4 m in length is fixed to a point on a smooth wall and the other end fastened to a point on the surface of a smooth sphere of diameter 2.25 m and of weight 100 kg. The tension in the string is

A. 17.5 kg

B. 19.5 kg

C. 22.5 kg

D. 25 kg.

220. One end of a light string 4 m in length is fixed to a point on a smooth wall and the other end fastened to a point on the surface of a smooth sphere of diameter 2.25 m and of weight 100 kg.The reaction between the sphere and the wall of the arrangement made, is

A. 102.5 kg

B. 105.5 kg

C. 108.5 kg

D. 110 kg.

221. On a mass m describing a circular path of radius r, the centrifugal force

A. acts tangentially to the circular path

B. acts towards the centre of rotation

C. acts away from the centre of rotation

D. is mw2rkfg.

222. A stone of mass 1 kg is tied to a string of length 1 m and whirled in a horizontal circle at a constant angular speed 5 rad/sec. The tension in the string is,

A. 5 N

B. 10 N

C. 15 N

D. 25 N

223. In a simple screw jack, the pitch of the screw is 9 nun and length of the handle operating the screw is 45 cm. The velocity ratio of the system is

A.1.5

B.5

C.25

D.314

224. A body of weight 14 g appears to weight 13 g when weighed by a spring balance in a moving lift. The acceleration of the lift at that moment was

A. 0.5 m/sec2

B. 0.7 m/sec2

C. 1 m/sec2

D. 1 cm/sec2.

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