Question

A boy lifts a 5 kg mass from the ground up to a
height of 2 m. How much work does the boy do on
the mass? [Take g = 10 m/s^2].​

Answer 1

=490.5 Joules

Explanation:

Work = Force * Distance

(I’m using an asterisk to denote multiplication)

Force (in Newtons) exerted by a mass m is: F = m * g

(assuming we are on Earth, that is)

where g is the acceleration due to gravity, 9.81 m/s/s

Therefore Work = Mass * g * Distance

= 10 * 9.81 * 5

=490.5 Joules

Answer 2

Given :-

Mass lifted by the boy = 5 kg

Height of the object lifted = 2 m

To Find :-

The work done by the body on mass.

Analysis :-

Here we are given with the mass and the height.

In order to find the work done substitute the given values from the questions accordingly such that work done is equal to mass into gravity into height.

Solution :-

We know that,

• m = Mass
• w = Work done
• g = Gravity
• h = Height

Using the formula,

$\underline{\boxed{\sf Potential \ energy=Mass \times Gravity \times Height}}$

Given that,

Mass (m) = 5 kg

Gravity (g) = 10 m/s

Height (h) = 2 m

Substituting their values,

⇒ w = mgh

⇒ w = 5 × 10 × 2

⇒ w = 50 × 2

⇒ w = 100 J

Therefore, the work done by the boy on mass is 100 J.