Work and Energy...

An object of mass $$5 \,kg$$ falls from a height of $$5 \,m$$ above the ground. The loss of potential energy of the mass is:

A car is accelerated on a leveled road and attains a velocity $$4$$ times its initial velocity. In this process, the potential energy of the car:

When a boy triples his speed, his kinetic energy becomes 

The $$S.I. $$ unit of work is 

Two coolies $$ A $$ and $$B$$ do same work in time $$ 1$$ minute and $$ 2 $$ minute respectively. The power spent is  

The decrease in the potential energy of a ball of mass $$ 20 kg $$ which falls from a height of $$ 50 cm  $$ is  

A body at rest may have 

If the stone is thrown up vertically and return to ground, its potential energy is maximum 

If velocity of a body is twice of previous velocity, then kinetic energy will become

A man does a given amount of work in 10 sec. Another man does the same amount of work in 20 sec. The ratio of the output power of first man to the second man is