A body of mass m accelerates uniformly from rest to v₁ in time t₁. As a function of time t, the instantaneous power delivered to the body is 

(1) $\frac{m{v}_{1}t}{t_1}$

(2) $\frac{m{v}_1^{2}t}{t_1}$

(3) $\frac{m{v}_1{t}^2}{t_1}$

(4) $\frac{m{v}_1^{2}t}{t_1^2}$

A weight lifter lifts 300 kg from the ground to a height of 2 meter in 3 second. The average power generated by him is 

(1) 5880 watt

(2) 4410 watt

(3) 2205 watt

(4) 1960 watt

The average power required to lift a 100 kg mass through a height of 50 metres in approximately 50 seconds would be 

(1) 50 J/s

(2) 5000 J/s

(3) 100 J/s

(4) 980 J/s

The power of a pump, which can pump 200kg of water to a height of 200m in 10sec is (g = 10 m/s²) 

(1) 40 kW

(2) 80 kW

(3) 400 kW

(4) 960 kW

A 60 kg man runs up a staircase in 12 seconds while a 50 kg man runs up the same staircase in 11, seconds, the ratio of the rate of doing their work is 

(1) 6 : 5

(2) 12 : 11

(3) 11 : 10

(4) 10 : 11

What average horsepower is developed by an 80 kg man while climbing in 10 s a flight of stairs that rises 6 m vertically 

(1) 0.63 HP

(2) 1.26 HP

(3) 1.8 HP

(4) 2.1 HP

An engine pumps up 100 kg of water through a height of 10 m in 5 s. Given that the efficiency of the engine is 60% . If g = 10 ms^–2, the power of the engine is

(1) 3.3 kW

(2) 0.33 kW

(3) 0.033 kW

(4) 33 kW

An engine pump is used to pump a liquid of density ρ continuously through a pipe of cross-sectional area A. If the speed of flow of the liquid in the pipe is v, then the rate at which kinetic energy is being imparted to the liquid is

(1) $\frac{1}{2}A\rho v^3$

(2) $\frac{1}{2}A\rho v^2$

(3) $\frac{1}{2}A\rho v$

(4) $A\rho v$

A shell initially at rest explodes into two pieces of equal mass, then the two pieces will 

(1) Be at rest

(2) Move with different velocities in different directions

(3) Move with the same velocity in opposite directions

(4) Move with the same velocity in same direction