Advertisements
Advertisements
प्रश्न
Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
Advertisements
उत्तर
Given:
Force (F) = 10 N,
Displacement (s) = 30 cm
= 30 × 10−2 m
Find: Work done (W) = ?
Formula: W = F × s
Calculations:
W = 10 × 30 × 10−2
W = `(10 xx 30)/100`
W = 3 J
Work done by Ravi is 3 J.
APPEARS IN
संबंधित प्रश्न
Define 1 J of work.
MULTIPLE CHOICE TYPE
In an electric cell which in use, the change in energy is from:
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)
How much work is done when a body of mass m is raised to a height h above the ground?
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?
What should be the angle between the direction of force and the direction of motion of a body so that the work done is zero?
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?
State the conditions of equilibrium for a rigid body.
Write an expression for the work done against gravity.
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
Electrical energy changes to heat energy.
Calculate the work done when:
A 5 kg weight is lifted 10 m vertically. (g = 9.8 m/s2)
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’.
Suma is swimming in a pond.
A force of F = (5y + 20) `hat"j"` N acts on a particle. The work done by this force when the particle is moved from y = 0 m to y = 10 m is ______ J.
