Question

When a power of 310 watts is applied to it, a pulley lifts box A one meter. The same pulley is used to lift box B. When the same amount of power is applied to box B, it is raised two meters. What can you say about the mass of the two boxes?

A. The mass of box A is half the mass of box B.
B. The mass of box A is three times the mass of box B.
C. The mass of box A is one–third the mass of box B.
D. The mass of box A is double the mass of box B.

Answer 1

C. The mass of box A is one–third the mass of box B.

Answer 2

D. The mass of box A is double the mass of box B.

Step-by-step explanation:

Given,

The power applied to box A = The power applied to box B

⇒ Potential energy of box A = Potential energy of box B

⇒
`m_1gh_1=m_2gh_2`

Where,
`m_1` and
`m_2` are the masses of boxes A and B respectively,

`h_1` and
`h_2` are the heights for box A and B respectively,

And, g is the acceleration due to gravity,

⇒
`m_1h_1=m_2 g_2`

Here,
`h_1` = 1 meter and
`h_2` = 2 meters,

⇒
`m_1=2m_2`

⇒ The masses of box A is double the mass of box B.

Option D is correct.