Advertisements
Advertisements
Question
A person of mass 50 kg climbs a tower of height 72 metres. Calculate the work done. (g = 9.8 m s−2).
Advertisements
Solution
Mass of the body, (m) = 50 kg
Height above the ground, (h) = 72 m
Acceleration due to gravity, (g) = 9.8 m/s2
We can calculate the work done against gravity as,
Work done in lifting a body = Weight of body × Vertical distance
So,
W = m × g × h
So work done,
W = 50 × 9.8 × 72 J
= 35280 J
So, the work done by the man is 35280 J.
APPEARS IN
RELATED QUESTIONS
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (see the given figure). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
A car is being driven by a force of 2.5 ✕ 1010 N. Travelling at a constant speed of 5 m/s, it takes 2 minutes to reach a certain place. Calculate the work done.
How much work is done when a force of 2 N moves a body through a distance of 10 cm in the direction of force?
No work is done by a man moving on a horizontal road while carrying a box on his head. Explain.
Name the physical quantity whose MKS units are kgm2s-3.
Define Translational motion.
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
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
A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?
