Advertisements
Advertisements
प्रश्न
State whether the following statement is True or False.
A boy does work while pushing a wall.
Advertisements
उत्तर
This statement is false.
Explanation:
In physics, work is defined as force multiplied by displacement. Pushing a wall requires using force, yet the wall does not move (displacement is zero), hence the labor done is zero.
APPEARS IN
संबंधित प्रश्न
What do you understand by a machine?
State if the following statement is true or false. Correct the statement if it is false.
Work done by a machine is always more than the work done on a machine.
Answer the following in short.
Mention any two methods by which we can take care of machines.
Give scientific reason for the following:
Passengers in a bus are pushed backward when it starts suddenly.
What is the relationship between the mechanical advantage and the velocity ratio for:
(i) An ideal machine,
(ii) A practical machine.
Give an example of the following use of a machine to change the direction of force.
(i) Calculate the mechanical advantage of the lever shown in the figure.
(ii) How do you define the mechanical advantage of a machine?

A cook used a ‘fire tong pair’ of length 32 cm. to lift a piece of burning coal of mass 500 g. If he applies his effort at a distance of 8 cm from the fulcrum, what is his effort? Assume friction etc. to be absent. Also, obtain values of the M.A. and the V.R. of this ‘machine’.
Classify the following as a lever, a pulley and an inclined plane:
A knife
Which machine will you use to do the following work? Write their type.
To hold a papad for roasting it.
