(d) all will reach the ground at the same time
Ans: (d)
36.Railway tracks are banked on curves so that
   (a) the necessary centrifugal force may be obtained from the horizontal
       component of the weight of the train
   (b) the frictional force between the track and the wheels is avoided
   (c) the necessary centripetal force may be derived from the horizontal
       component of the weight of the train
   (d) None of these
Ans: (c)
37.A boy is swinging a ball attached to a string in a horizontal circle. If the
   string snaps
   (a) the ball will travel towards the centre of the circle and fall down
   (b) it will continue to travel along a tangent to the circle at the point the ball
       was at the time of snapping and finally fall down
   (c) it will fall down at the same place where the string breaks
   (d) None of these
Ans: (b)
38.The period of oscillation of a simple pendulum depends upon
   (a) the mass of its bob
   (b) the material of the bob
   (c) the amplitude of vibration
   (d) acceleration due to the gravity at the site of experiment
Ans: (d)
39.If a body weight 12N on the surface of the earth, how much will it weigh on
   the surface of the moon where acceleration due to gravity is only one-sixth
   of that on earth"s surface?
   (a) 12N
   (b) 2N
   (c) 10N
   (d) 6N
Ans: (b)