Physics Test 15...

A pump on the ground floor of a building can pump up water to fill a tank of volume 30 m³ in 15 min. If the tank is 40 m above the ground, and the efficiency of the pump is 30%,  how much electric power is consumed by the pump?

A trolley of mass 200 kg moves with a uniform speed of 36 km/h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of 4 ms⁻¹ relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. How much has the trolley moved from the time the child begins to run?

If a man increases his speed by 2 m/sec, his K.E. is doubled. The original speed of the man is-

A force  Newton (where x is in metres) acts on a particle which moves from a position (2m, 3m) to (3m, 0m). Then the work done is

The angular position of a particle (in radians), along a circle of radius 0.8 m is given by the function in time (seconds) by  The linear velocity of the particle

Which of the following is not a unit of angular displacement?

A boy is playing with a tire of radius 0.5m. He accelerates it from 5rpm to 25 rpm in 15 seconds. The linear acceleration of tire is

In an equilateral triangle of length 6 cm , three masses m₁= 40g , m₂= 60g and m₃= 60g are located at the vertices. The moment of inertia of the system about an axis along the altitude of the triangle passing through m₁ is

For a system to be in equilibrium, the net torques acting on it must balance. This is true only if the torque are taken about

The Mechanical advantage of a lever is given by-