851. Work done will be maximum if the angle between the force F and displacement d is
A. 45°
B. 90°
C. 180°
D. 0°

852. A field in which the work is done in a moving a body along a closed path is zero is called
A. Electric field
B. Conservative field
C. Electromagnetic field
D. Gravitational field

853. When a force is parallel to the direction of motion of the body, then work done on the body is
A. Zero
B. Minimum
C. Infinity
D. Maximum

854. Which of the following types of force can do no work on the particle on which it acts?
A. Frictional force
B. Gravitational force
C. Elastic force
D. Centripetal force

855. If a body a mass of 2 kg is raised vertically through 2m, then the work done will be
A. 38.2 J
B. 392.1 J
C. 39.2 J
D. 3.92 J

856. An elevator weighing 3.5 x 10-6 N is raised to a height of 1000 m in the absence of friction, the work done is
A. 3.5 x 103 J
B. 3.5 x 104 J
C. 3.5 x 106 J
D. 3.5 x 109 J

857. The average power and instantaneous power become equal if work is done at
A. Any rate
B. At variable rate
C. At a uniform rate
D. At a high rate

858. The relation between horsepower and watt is
A. 1 hp = 546 watts
B. 1 hp = 746 watts
C. 1 hp = 1000 watts
D. 1 hp = 946 watts

859. Proton-electron neutron and particles have the same momentum. Which of them have highest K.E?
A. Proton
B. Electron
C. Neutron
D. A-particle

860. The slope of the work time graph is equal to
A. Displacement
B. Acceleration
C. Power
D. Energy