Question

(a) Find the energy possessed by a box of mass 6000 g when it is at a height of 5 m above the ground.name the form of energy this box possesses.

Answer 1

Provided that:

• Mass of a box = 6000 grams
• Height above the ground = 5 m

To calculate:

• The energy

Solution: The energy possess by the box is 294 Joules

Knowledge required:

• The value of g is 9.8 m/s²

• g denotes acceleration due to gravity

• SI unit of mass is kg

➜ Potential energy = The capacity of doing work developed in a body due to it's position or configuration is known as potential energy like, ⑴ energy of stretched or compressed string ⑵ energy of spring in a watch ⑶ energy of water collected at a height.

PE of a body is the gravitational field of earth is ${\sf{mgh}}$

[Where, m denotes mass , g denotes acceleration due to gravity and h denotes height of the body from the surface of the earth]

Using concepts:

• Potential energy formula
• Formula to convert g into kg

Using formula:

• ${\sf{E_p \: = mgh}}$

• ${\sf{1 \: g \: = \dfrac{1}{1000} \: kg}}$

Required solution:

~ Firstly let us convert g into kg

$:\implies \sf 1 \: g \: = \dfrac{1}{1000} \: kg \\ \\ :\implies \sf 6000 \: g \: = \dfrac{6000}{1000} \: kg \\ \\ :\implies \sf 6000 \: g \: = \cancel{\dfrac{6000}{1000}} \: kg \\ \\ :\implies \sf 6000 \: g \: = 6 \: kg \\ \\ {\pmb{\sf{Henceforth, \: converted!}}}$

~ Now let's find the energy!

$:\implies \sf E_p \: = mgh \\ \\ :\implies \sf E_p \: = 6(9.8)(5) \\ \\ :\implies \sf E_p \: = 6 \times 9.8 \times 5 \\ \\ :\implies \sf E_p \: = 30 \times 9.8 \\ \\ :\implies \sf E_p \: = 294.0 \: J \\ \\ :\implies \sf Potential \: energy \: = 294.0 \: Joules \\ \\ {\pmb{\sf{Henceforth, \: solved!}}}$

~ Now let's carry on!

The form of energy this box possesses is potential energy!