Advertisements
Advertisements
Question
A boy of mass 40 kg runs up a height of 30 steps, each 20 cm high. Find:
(i) The force of gravity acting on the boy.
(ii) The work done by the boy against gravity. (Take g = 9.8 ms−2)
Advertisements
Solution
Given : m = 40 kg, g = 9.8 ms−2
Distance moved, d = 30 × 20 cm = 600 cm = 6 m.
(i) The force of gravity, F = mg = 40 × 9.8 = 392 N.
(ii) The work done by the boy, W = F × d = 392 × 6 = 2352 J.
RELATED QUESTIONS
Explain the motion of a planet around the Sun in a circular path.
Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G.
Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G.
Even though the Tower of Pisa is leaning through an angle it does not fall.
Explain why Standing passengers are not allowed on the upper deck of a double-decker bus.
What is centre of gravity ?
Mention the real-life applications of the center of gravity.
In a non-uniform gravitational field, how does the Centre of Gravity relate to the Centre of Mass?
