Question

a man takes a body of 50 kg on the roof of a bus 2.5 M find how much work has he to do against gravitational force?(g=9.8m/s²)

Answer 1

Force = m×g ×h
= 50× 9.8 × 2.5
1225 Newton

Answer 2

Weight is the force exerted on you by gravity, of any object. Since weight is a force and gravitational “pull” is an acceleration, we can use the equation F=ma to work out the weight:

F=m*a

F=50kg * 9.80665 m/s^2 (Gravity on Earth’s surface)

F=490.3325 N (N stands for Newtons, and is the unit for Force). We can round this up to 490N, just like we can round 9.80665 to 9.8.

Note that gravity varies from place to place on Earth, so your weight is a bit different here than in Japan (not by much). 9.80665 m/s^2 is what we call “standard” gravity on Earth.

A lot of times, people will confuse mass and weight. Mass is the amount of matter that composes something, and weight, as I said, is a Force exerted on mass.