A body of mass m kg is lifted by a man to a height of one meter in 30 sec. Another man lifts the same mass to the
same height in 60 sec. The work done by them are in the ratio
A man M1 of mass 80 kg runs up a staircase in 15s. Another man M2 also of mass 80 kg runs up the same staircase in 20s. The ratio of the power developed by them will be
Figure represents a graph of kinetic energy (K) of the photoelectrons (in eV) and frequency (v) for a metal used as cathode in photoelectric experiment. The work function of metal is:
Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and
v respectively. These trucks collide and stick together.
What is the speed of the trucks after the collision?