Answer:
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