1. You are hired to lift 25 kg crates a vertically 1.0 m from the ground onto a truck. How many crates would you have to load onto the truck in 1 minute for your average power output in lifting the crates to be 110 W

The number of crate to be lifted is 27

Explanation:

Given;

mass of the crates, m = 25 kg

height in which the crate is lifted, h = 1.0 m

power output, P = 110 W

time to complete the task, t = 1 minutes = 60 s

The input energy is equal to the gravitational energy due to height the crate is lifted is given as;

E(input) = mgh

E(input)  = 25 x 9.8 x 1

E(input)  = 245 J

Output energy is given as;

E(output) = P x t

E(output) = 110 x 60

E(output) = 6600 J

Let the number of crate to be lifted = n

n x E(input)  = E(output)

n x 245 = 6600

n = 6600 / 245

n = 27 crates

answer; i believe that the correct answer is (d) a very small amount of mass