Advertisements
Advertisements
Question
For the following scenarios, state whether the work done by gravity is positive, negative, or zero.
A person climbs a ladder.
Solution
Negative work is done.
APPEARS IN
RELATED QUESTIONS
A body is provided at a point. A force of 20 N is applied at a distance of 40 cm from the pivot. Find the moment of force about the pivot.
What do you mean by a centrifugal force?
A man raises a box of mass 50 kg to a height of 2 m in 20s, while another man raises the same box to the same height in 50s. Calculated:
- the work done, and
- the power developed by each man. Take g = 10 N kg-1.
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. Compare:
- the work, and
- power developed by them.
State and define the unit of force in the S.I. system.
In the following case write yes, if the work is being done and no if no work is being done.
A man trying to push a wall.
A force F when acts on a body, displace it by a distance d in a direction at an angle θ with the direction of the force. Write down the expression for the work done by the force.
State two conditions for work to be done.
What happens to the power if the time for doing work is reduced from t second to t/10 second?
Calculate the work done when:
A car is moved on a rough road through 30 m against a frictional resistance of 75 N.