Question

How high should a hammer of mass 3 Kg be raised, so that it acquires a potential energy of 45J

Answer 1

Provided that:

• Mass = 3 kg
• Potential energy = 45 Joules

To calculate:

• The height

Solution:

• The height = 1.53 m

Using concept:

• Potential energy formula

Using formula:

• ${\small{\underline{\boxed{\pmb{\sf{E_p \: = mgh}}}}}}$

Where, E_p denotes potential energy, m denotes mass, g denotes acceleration due to gravity and h denotes height.

Knowledge required:

• The value of g that is acceleration due to gravity is 9.8 metre per second sq.

Required solution:

~ Let us solve this question by using potential energy formula!

»»» E_p = mgh

»»» 45 = 3(9.8)(h)

»»» 45 = 29.4h

»»» 45/29.4 = h

»»» 1.53 = h

»»» h = 1.53 m

»»» Height = 1.53 metres.

• Henceforth, at a height of 1.53 metres should a hammer of mass 3 kg be raised, so that it acquires a potential energy of 45 Joules.

Additional information:

➜ 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 at the gravitational field of earth is ${\sf{mgh}}$

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