A helicopter of mass 2000 kg rises with a vertical acceleration of 15 m s^–2. The total mass of the crew and passengers is 500 kg. Give the magnitude and direction of the (g = 10 m s^–2)

(a) Force on the floor of the helicopter by the crew and passengers. 

(b) Action of the rotor of the helicopter on the surrounding air. 

(c) Force on the helicopter due to the surrounding air.

Two SHMs in same direction are represented by y1 = asinωt and y2 = asin(ωt + δ). When they superimpose, the initial phase difference of the resultant SHM is

The potential energy of a particle of mass 2 kg in motion along the x-axis is given by U = 2 (1 – cos 2x) J, where x is in meters. The period of small oscillations (in s) is

A child is standing with folded hands at the centre of a platform rotating about its central axis. The kinetic energy of the system is K. The child now stretches his arms so that the moment of inertia of the system becomes 3/2 of the initial moment of inertia. The kinetic energy of the system is now

If the absolute temperature of hot black body is raised by 2%, by how much percentage rate of heat energy radiated would be increased nearly?

Two moles of helium gas are taken over the cycle ABCDA as shown below in P-T diagram. Assuming the gas to be ideal, the work done on the gas in taking from A to B is