Advertisements
Advertisements
Question
A boy throws a rubber ball vertically upwards. What type of work, positive or negative, is done : by the force applied by the boy?
(a) by the force applied by the boy?
(b) by the gravitational force of earth?
Advertisements
Solution
A boy throws a rubber ball vertically upwards. Work done by the two forces:
(a) Work done by the force applied by the boy is positive because the displacement of the ball is in the direction of force applied.
(b) Work done by the gravitational force is negative because the displacement of the ball is opposite to the direction of gravitational force.
APPEARS IN
RELATED QUESTIONS
A man lifts a mass of 20 kg to a height of 2.5 m. Assuming that the force of gravity on 1 kg mass is 10 N, find the work done by the man.
Differentiate between energy and power.
Does the earth move around the sun with a uniform velocity?
A bullet is of mass 'm' g and is moving with a velocity 'v' m/s. Find the kinetic energy of the bullet when
(a) The mass is doubled,
(b) The velocity is tripled.
Is power a scalar or a vector quantity?
A ______ should act on an object.
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 ______.
State whether work is done or not, by writing yes or no, in the following case:
A man pushes a wall.
