Advertisements
Advertisements
प्रश्न
उत्तर
APPEARS IN
संबंधित प्रश्न
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (see the given figure). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
State two factors on which the work done on a body depends.
Define the term energy.
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.
When is work said to be done by a force?
MULTIPLE CHOICE TYPE
In an electric cell which in use, the change in energy is from:
State two disadvantages of producing hydroelectricity.
State the SI unit of work.
The velocity of a car increases from 54 km/hr to 72 km/hr. How much is the work done if the mass of the car is 1500 kg?
What is the relationship between Nm and dyne cm?
Give two examples of couple action in our daily life.
A boy does work when he pushes against a brick wall. (yes/no).
An object is dropped from a height H. when is its
(i) P.E. maximum,
(ii) K.E. maximum,
(iii) P.E. = K.E.?
List any six forms of energy and write a short note on each of them.
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).
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.
Define force. Is force a scalar or a vector quantity?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
