Advertisements
Advertisements
प्रश्न
A girl of mass 50 kg runs up a flight of 40 steps in 20 seconds. If each step in 20 cm high, calculate the power developed by the girl. (g= 10 ms-2).
Advertisements
उत्तर
Given, mass = 50kg
Total height traveled = 40 x 20 cm = 800 cm = 8 m
g = 10ms-2
time taken = 20s
work done = mgh = 50 x 10 x 8 = 4000 J
power = `"work done"/"time taken" = 4000/20 = 200 "watt"`
APPEARS IN
संबंधित प्रश्न
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
A vessel containing 50 kg of water is placed at a height 15 m above the ground. Assuming the gravitational potential energy at ground to be zero, what will be the gravitational potential energy of water in the vessel? (g = 10 m s-2)
A car is running at a speed of 15 km h-1 while another similar car is moving at a speed of 45 km h-1. Find the ratio of their kinetic energies.
Is the motion of moon around the earth in circular path an accelerated motion?
Define 'joule'.
A force can cause an object to change its ______.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A wind-mill is lifting water from a well.
A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car
