Question

A book of mass 400g is lifted from the floor onto a 1.2m high shelf. Calculate the increase n the gravitational potential energy of the book. Take g = 9.8N/kg

Answer 1

• 4.8 Joules

Step-by-step explanation:

The gravitational potential energy when raised to a height h is given as ,

`\implies PE = mgh \\\\`

where,

• m is mass of the body = 400g = 0.4kg
• g is acceleration due to gravity = 10m/s²
• h is height upto which the body is raised = 1.2m

On substituting the respective values, we have;

`\implies PE = 0.4kg * 1.2m * 10m/s^2\\\\`

`\implies PE = 4.8\ J\\\\`

At ground h = 0m , so the potential energy is 0. So the change in potential energy is equal to the final potential energy at height 1.2m.

Henceforth the potential energy increase in the book is 4.8J

Answer 2

The increase in gravitational potential energy of a 400g book lifted onto a 1.2m high shelf is calculated using the formula GPE = mgh, resulting in an increase of 4.704 joules.

Step-by-step explanation:

To calculate the increase in gravitational potential energy when lifting a book, we can use the formula Gravitational Potential Energy (GPE) = mgh, where m is the mass in kilograms, g is the acceleration due to gravity (9.8 N/kg on Earth), and h is the height in meters.

For a book with a mass of 400 g (which is 0.4 kg when converted to kilograms), lifted to a height of 1.2 m, the increase in gravitational potential energy can be determined as follows:

• m (mass) = 0.4 kg
• g (acceleration due to gravity) = 9.8 N/kg
• h (height) = 1.2 m

Now, apply these values to the GPE formula:

GPE = 0.4 kg × 9.8 N/kg × 1.2 m = 4.704 J

Thus, the increase in the gravitational potential energy of the book is 4.704 joules.