Advertisements
Advertisements
Question
In which of the following case the work done by a force will be maximum : when the angle between the direction of force and direction of motion is 0° or 90°?
Advertisements
Solution
The relation between work, force, distance and angle between the two is:
W = (F) (S) cos θ
Where,
(W) - Work done
(F) - Force
(S)- Displacement
(θ)- Angle between force and displacement
When the force is perpendicular to the direction of motion, and hence, the work done is also zero.
When the direction of force is similar the direction of motion, and hence, the work done is maximum.
APPEARS IN
RELATED QUESTIONS
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
A box of weight 150 kgf has gravitational potential energy stored in it equal to 14700 J. Find the height of the box above the ground. (Take g = 9.8 N kg-1)
A vessel containing 50 kg of water is placed at a height 15 m above the ground. Assuming the gravitational potential energy at ground to be zero, what will be the gravitational potential energy of water in the vessel? (g = 10 m s-2)
Is work a scalar or a vector quantity?
Each of the following statement describes a force acting. Which force is causing work to be done?
A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s−2, the work by her after climbing 2 m will be :
A cricket ball is thrown up from the earth's surface. What happens to its P.E.
(a) during the motion
(b) at the highest point?
State the energy changes which take place when An electric bulb glows when it is connected to a source of electric current.
Give an example
Chemical energy changes to electrical energy.
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.
