Numerical problems:
a. Find the force required to do 25 joule work when the force causes a
displacement of 0.5 m.--
A boy pushes a book by applying force of 5 N. Find the work done by this
force as the book is displaced through 20 cm while pushing.
Find the kinetic energy of a ball of mass 200 grams moving at a speed of 20 m/s.
A stone 'X' of mass 2 kg is at the height of 2 m from the ground level.
Another similar stone 'Y' of mass 4 kg is at the height of 4 m from the ground
level. What is the difference between their potential energy?
A 60 kg person climbs stairs of total height of 20 m in two minutes, calculate
the power delivered. (g = 10 ms-2]
How much time will it take to perform 440 joule of work at a rate of 11 W?
g. A 100 watt electric bulb is used for five hours. How much energy is consumed
by the bulb?
A coolie of 40 kg weight carries 20 kg salt and climbs up 20 steps of 20
centimeters each in 2 minutes. Calculate the work done by him and his power.
[g= 10 m/s2]