Advertisements
Advertisements
Question
A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
(i) Calculate the mechanical advantage of the inclined plane. (ii) Calculate the effort applied by the coolie.
(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.
Advertisements
Solution
(i) Mechanical Advantage (M.A.) = `"l"/"h"`
M.A. =`7.5/2.5=3`
(ii) M.A. =`("Load"("L"))/("Effort"("E"))`
3 = `(1,500)/"E"`
E = 500 N.
(iii) More effort is required becaues of friction.
RELATED QUESTIONS
Give reasons for the following. No work is done if a man is pushing against a wall.
MULTIPLE CHOICE TYPE
In an electric cell which in use, the change in energy is from:
State the conditions of equilibrium for a rigid body.
Does the earth move around the sun with a uniform velocity?
What is the work done when the object acted upon by a force remains at rest?
Can two agents, doing the same work, have different power?
Name two places in India where electricity is generated from nuclear power plants.
An electric motor of power 100 W is used to drive the stirrer in a water bath. If 50% of the energy supplied to the motor is spent in stirring the water. Calculate the work done on the water in one minute.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
An engine is pulling a train.
