Advertisements
Advertisements
Question
A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.
Advertisements
Solution
- The mass of 10 kg is transported horizontally from point A to B. Gravity acts vertically downward. Thus, the mass moves at a right angle to the force of gravity. So,
- Work done on the item by the force of gravity = Fs cosθ = Fs cos90° = 0 (∵ cos 90 = 0).
- Therefore, the gravitational pull on the object does not work.
APPEARS IN
RELATED QUESTIONS
State two factors on which the potential energy of a body at a certain height above the ground depends.
A body of mass m is moved from ground to a height h. If the force of gravity on mass of 1 kg is g newton, find the force needed to lift the body.
Find the gravitational potential energy of 2.5 kg mass kept at a height of 15 m above the ground. The force of gravity on mass 1 kg is 10 n.
Define the term potential energy of a body.
A ball of mass m is thrown vertically up with an initial velocity so as to reach a height h. The correct statement is:
To what height should a box of mass 150 kg be lifted, so that its potential energy may become 7350 joules? (g = 9.8 m/s2)
Explain by an example what is meant by potential energy. Write down the expression for gravitational potential energy of a body of mass m placed at a height h above the surface of the earth.
What is the difference between gravitational potential energy and elastic potential energy? Give one example of a body having gravitational potential energy and another having elastic potential energy.
If we increase the velocity of a car moving on a flat surface to four times its original speed, its potential energy ______.
The potential energy of your body is least when you are ______.
