Physics Chapter 2 Entry test MCQs
76. The figure shows the force distance curve of a body moving along a straight line. The work done by the force
a. 10J
b. 30J
c. 20J
d. 40J
77. A man of mass 60 kg climbs up a 20m long staircase to the top of a building 10m high What is the work done by him: Take g=10ms-²
a. 3 KJ
b. 6 KJ
c. 12 KJ
d. None he above
78. When a force retards the motion of a body the work done is:
a. Positive
b. Zero
c. Positive or negative depending upon the magnitude of force and displacement
d. Negative
79. An engine pumps out 40 kg of water in one second. The water comes out vertically upwards with a velocity of 3ms-¹, the power of engine in kilowatt is:
a. 120 kW
b. 1.2 kW
c. 1200 kW
d. 12 kW
80. Two boys weighing in the ratio 4:5 goes up stair taking time in the ratio 5:4. The ratio of their power is:
a. 25/16
b. 1
c. 4/5
d. 16/25
81. Energy consumed by 60-watt bulb in 2 minutes is equal to
a. 720 joules
b. 7.2 kilo joules
c. 72000 joules
d. 120 joules
82. A stone of mass 2.0 kg is dropped from a rest position 5.0m above the ground. What is its velocity at a height of 3.0m above the ground?
a. 6.3m/s
b. 12.5m/s
c. 16.0m/s
d. 9.3m/s
83. The rate at which work is being done is called:
a. Energy
b. Power
c. Force
d. Density
84. A man has a mass of 80 kg. He ties himself to one end of rope which passes over a single fixed pulley. He pulls on the other end of the rope to lift himself up at an average speed of 50cms. What is the average useful power at which he is working?
a. 4.0kW
b. 40W
c. 39kW
d. 0.39kW
85. If the momentum of a body decreases by 20% the percentage decreases in K.E will be:
a. 28%
b. 44%
c. 20%
d. 36%
86. A man carries a 1 kg body 10m horizontally on a level ground. The work zone by the man is:
a. OJ
b. 10 J
c. 5 J
d. 1J
87. An automobile is moving forwards with uniform velocity due to the force exerted by its engine. If that force is double with the velocity remaining constant what happens to its total power?
a. It is squared
b. It does not change
c. It is doubled
d. It is halved
88. Which of the following statement shows that no work is done?
a. Writing an essay on a page
b. Pushing a car to start it moving
c. The moon orbiting the earths
d. Lifting the weights
89. A 1.75 m heighted weight-lifter raises weights with a mass of 50 kg to a height of .5m above his head. How much work is being done by him? (g=10ms-²)
a. 50J
b. 2125J
c. 1225 J
d. 2500 J
90. When the speed of your car is halved, by what factor does its kinetic energy decreases?
a. 1/8
b. 1/2
c. 1/6
d. 1/4
91. Which of the following force is non-conservative force?91.
a. Electric force
b. Fractional force
c. Elastic spring force
d. Gravitation force
92. The area under force – displacement graph gives us:
a. Work
b. Displacement
c. Acceleration
d. Power
93. Kilowatt-hour is unit of?
a. Momentum
b. Electric energy
c. Torque
d. Power
94. A field in which the work is done in a moving a body along a closed path is zero is called
a. Electromagnetic field
b. Electric field
c. Gravitational field
d. Conservative field
95. When a force is parallel to the direction of motion of the body, then work done on the body is
a. Infinity
b. Zero
c. Maximum
d. Minimum
96. If a body a mass of 2 kg is raised vertically through 2m, then the work done will be
a. 39.2 J
b. 38.2 J
c. 3.92 J
d. 392.1 J
97. The relation between horsepower and watt is
a. 1 hp=1000 watts
b. 1 hp=546 watts
c. 1 hp=946 watts
d. 1 hp=746 watts
98. The area under the force displacement graph represents
a. Power
b. Work done
c. Area
d. None of these
99. A machine does 2500 J of work in 1 min. What is the power developed by the machine?
a. 150 W
b. 21 W
c. 2500 W
d. 42 W
100. A moving car possesses
a. Heat energy
b. Sound energy
c. Chemical energy
d. Mechanical energy
101. kWh is the unit of
a. Time
b. Force
c. Energy
d. Power
102. 2kg mass is uplifted by the machine through the height of 200m for 10 sec. calculate power deliver to the load. (g=10m/s²)
a. 440W
b. 40W
c. 200W
d. 400W
103. Light body A and heavy body B have equal K. E of translation. Then
a. A and B have same momentum
b. B has larger momentum than A
c. A has lager momentum than B
d. None
104. If momentum is increased by 13% then K.E increase by
a. 3.47%
b. 37%
c. 2.27%
d. None