51. When two bodies move toward each other with constant speeds the distance between them decreases at the rate of 6m / sec. If they move in the same direction the distance between them increases at the rate of 4m/sec. Then their speeds are________________?

A. 5m/s, 1m/s
B. 3m/s, 3m/s
C. 6m/s, 1m/s
D. 4m/s, 2m/s

52. The distance covered by a body in time t starting from rest is__________________?

A. at2/2
B. Vt
C. a2t/2
D. at2

53. The trajectory (or path) of a projectile is_________________?

A. straight line
B. parabola
C. hyperbola
D. circle

54. The force beared by a wall on which water strikes normally at a speed of 10m/sec and at a discharge of 0.0001m3/sec is__________________?

A. 1 N
B. 10 N
C. 100 N
D. none

55. The range of the projectile at 30 deg and 60 deg are__________________?

A. equal to 45 deg
B. equal to 90 deg
C. equal to each other
D. none of the above

56. Waves transmit ________________ from one place to another?

A. energy
B. mass
C. both
D. none

57. When collision between the bodies in a system is inelastic in nature then for system ____________________?

A. momentum changes but K.E remain conserve
B. K.E changes but momentum remain conserve
C. both momentum and K.E changes
D. both momentum and K.E remain conserve

58. The acceleration in the rocket at any instant is proportional to the nth power of the velocity of the expelled gases. Where the value of n must be ?

A. -1
B. 1
C. 2
D. -2

59. Which of the following is not an example of projectile motion ?

A. a gas filled balloon
B. bullet fired from gun
C. a football kicked
D. a base ball shot

60. The thrust on the rocket in the absence of gravitational force of attraction is__________________?

A. Constant
B. not constant
C. constant if the rate of ejected gases is constant
D. constant for short range rocket.