Question

A brick of mass 300 g is dropped from a height of 20 m. What is the work done on the brick by gravity when it reaches the halfway mark?

Answer 1

Answer:

Work = 2943 J

Explanation:

So first you want to figure out what you have and what you need (CONVERT TO THE BASIC UNITS TOO!!)

you have:

Mass = 300g = 30.0 Kg

Distance or displacement across y axis: 20m, but since it is only till the half mark you want to use 10m

Now you need to figure out what you need. the equation for work is Work = Force x Distance or displacement

what you need is the force of gravity so the equation that you tecnically need is Work of gravity = force of gravity x distance

to find the force of gravity you need to use the equation force = mass x acceleration or force of gravity (Fg)= mass x acceleration of gravity (Ag).

so...

Fg = M x Ag

Fg = 30 x 9.81

Fg = 294.3 N

Now you can plug in what you have to the Work equation

W = F x D

W = 294.3 N x 10 m

W = 2943 J

I hope this helps!

Please tell me if I'm incorrect anywhere.