Question

A 22 kg sled is pushed for 5.2 m with a horizontal force of 20 N, starting from rest. Ignore friction. Find the final speed of the sled.

Answer 1

Note that this force does
`20 \, N \cdot 5.2 \, m = 104 \, J` of work. Then, by conservation of energy, we have that:


`(mv^2)/(2) = 104 \, J`

Substituting
`m=22 \, kg`, we see that:


`11v^2 \, kg = 104 \, J`

Then, dividing by
`11` and taking the square root, we see that:


`v=~3.1 \, m/s`