Advertisements
Advertisements
Question
A man carrying a suitcase in his hand is walking horizontally. What is the work done against gravity?
Advertisements
Solution
The displacement of the man and suitcase is along the horizontal direction. Thus, the angle between the displacement and the force of gravity is 90°;
Thus, W = Fd cos 90° = 0
Hence, no work is done against gravity in this case.
APPEARS IN
RELATED QUESTIONS
State the S.I. unit of work and define it.
A body, when acted upon by a force of 10 kgf, moves to a distance 0.5 m in the direction of force. Find the work done by the force. Take 1 kgf = 10 N.
It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B does the same in 15 s. Compare the work done.
The power of a motor is 40 kW. At what speed can the motor raise a load of 20,000 N?
Is it possible that a force is acting on a body but still the work done is zero? Explain giving one example.
Draw a neat labeled diagram to show the direction of two forces acting on a body to produce rotation in it. Also mark the point about which rotation takes place.
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
Fill in the boxe to show the corresponding energy transformation.
Name the material commonly used for the manufacturing of solar cells.
A body of mass 0.5 kg travels on straight line path with velocity v = (3x2 + 4) m/s. The net work done by the force during its displacement from x = 0 tox = 2 m is ______.
