Work, Energy and Power Test

Result

Work, Energy and Power Test - 81

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Weekly Quiz Competition

Question 1
4 / -1

Two springs A and B are identical but A is harder than B(k_A > k_B ). Let W_A and W_B represent the work done when the springs are stretched through the same distance and W’_A and W’_B are the work done when these are stretched by equal forces, then which of the following is true

A
W_A > W_B and W’_A = W’_B

B
W_A > W_B and W’_A < W’_B

C
W_A > W_B and W’_A > W’_B

D
W_A < W_B and W’_A < W’_B

Solution
Question 2
4 / -1

A car of mass \'m\' is driven with acceleration \'a\' along a straight level and against a constant external resistive force \'R\'. When the velocity of the car is \'V\' the rate at which the engine of the car is doing work will be

A
RV

B
maV

C
(R + ma)V

D
(ma – R)V

Solution
Question 3
4 / -1

A vertical spring with force constant K is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d. The net work done in the process is

A

B

C

D
Question 4
4 / -1

A frictionless track ABCDE ends in a circular loop of radius R. A body slides down the track from point A which is at a height h = 5 cm. Maximum value of R for the body to successfully complete the loop is

A
5 cm

B

C

D
2 cm

Solution
Question 5
4 / -1

A running man has half the kinetic energy of that of a body of half of his mass. The man speeds up by 1 m/s so as to have same K.E. as that of the boy. The original speed of the man will be

A

B

C

D

Solution
Question 6
4 / -1

A sphere of mass m moving with a constant velocity u hits another stationary sphere of the same mass. If e is the coefficient of restitution, then the ratio of the velocity of two spheres after collision will be

A

B

C

D
Question 7
4 / -1

A canon ball is fired with a velocity 200 m/sec at an angle of 60° with the horizontal. At the highest point of its flight it explodes into 3 equal fragments, one going vertically upwards with a velocity 100 m/sec, the second one falling vertically downwards with a velocity 100 m/sec. The third fragment will be moving with a velocity

A
100 m/s in the horizontal direction

B
300 m/s in the horizontal direction

C
300 m/s in a direction making an angle of 60° with the horizontal

D
200 m/s in a direction making an angle of 60° with the horizontal

Solution
Question 8
4 / -1

A billiards player hits a stationary ball by an identical ball to pocket the target ball in a corner pocket that is at an angle of 35° with respect to the direction of motion of the first ball. Assuming the collision as elastic and that friction and rotational motion are not important, the angle made by the target ball with respect to the incoming balls is

A
35^o

B
50^o

C
55^o

D
60^o
Question 9
4 / -1

A ball hits the floor and rebounds after inelastic collision. In this case

A
The momentum of the ball just after the collision is the same as that just before collision

B
The mechanical energy of the ball remains the same in the collision

C
The total momentum of the ball and the earth is conserved

D
The total energy of the ball and the earth is conserved
Question 10
4 / -1

Two identical cylindrical vessels with their bases at same level each contains a liquid of density ρ. The height of the liquid in one vessel is h₁ and that in the other vessel is h₂. The area of either base is A. The work done by gravity in equalizing the levels when the two vessels are connected, is

A
(h₁ – h₂)gρ

B
(h₁ – h₂)gAρ

C

D

Solution