A stone of mass 0.05 kg is thrown vertically upwards. What is the direction and magnitude of net force on the stone during its upward motion ?
0.98 N vertically downwards
0.49 N vertically downwards
9.8 N vertically downwards
0.49 N vertically upwards
A 12 kg bomb at rest explodes into two pieces of 4 kg and 8 kg. If the momentum of 4 kg piece is 20 Ns, the kinetic energy of the 8 kg piece is
25 J
20 J
50 J
40 J
A motor pump lifts 6 tonnes of water from a well of depth 25 m to the first floor of height 35 m from the ground floor in 20 minutes. The power of the pump (in kW) is [g = 10 ms-2]
3
12
15
6
The energy spectrum of a black body exhibits a maximum around a wavelength λ0. The temperature of the black body is now changed such that the energy is maximum around a wavelength . The power radiated by the black body will now increase by a factor of
64/27
256/81
4/3
16/9
n identical bulbs, each designated to draw a power P from a certain voltage supply. The total power which they will draw is
nP
P