Advertisements
Advertisements
प्रश्न
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?
उत्तर
Given:
Initial velocity of the car (u) = 54 km/hr
= `(54 xx 1000)/3600` m/s
= 15 m/s
Final velocity of the car (v) = 72 km/hr
= `(72 xx 1000)/3600` m/s
= 20 m/s
Mass of the car (m) = 1500 kg
Find: Work done (W)
Formula: Work done (W) = Final kinetic energy - Initial kinetic energy
Calculations:
W = `1/2"mv"^2 - 1/2"mu"^2`
W = `1/2"m"("v"^2 - "u"^2)`
W = `1/2 xx 1500(20^2 - 15^2)`
= `1/2 xx 1500(400 - 225)`
= `1/2 xx 1500 xx 175`
W = 131250 J
Work done to increase the speed of the car 131250 J.
APPEARS IN
संबंधित प्रश्न
Explain briefly why the work done by a fielder when he takes a catch in a cricket match is negative.
Work done by a boy depends on the time in which he does work.
Work done = Force × ........................................
Define 1 joule of energy.
Differentiate between energy and power.
.A man raises a box of mass 50kg to a height of 2m in 20s, while another man raises the same box to the same height in 50s. Compare:
(i) the work done, and
(ii) the power developed by them.
State the law of conservation of energy.
What do you mean by degradation of energy?
A force of 50 N acts on a body and moves it a distance of 4 m on horizontal surface. Calculate the work done if the direction of force is at an angle of 60° to the horizontal surface.
Why is the work done on an object moving with uniform circular motion zero?
On what factors does the work done by a force depend?
A canon ball of mass 500g is fired with a speed of 15m/s-1. Find: its momentum.
Calculate the work done when:
A 5 kg weight is lifted 10 m vertically. (g = 9.8 m/s2)
A ______ should act on an object.
What is work?
Force acting on a particle moving in a straight line varies with the velocity of the particle v as F = `K/v`, where K is a constant. The work done by this force in time t is
