Question

A dockworker applies a constant horizontal force of 79.0 N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves a distance 13.0 m in a time 4.50 s. What is the mass of the block of ice?If the worker stops pushing at the end of 4.50 s, how far does the block move in the next 4.70 s?

Answer 1

Use the statement
" The block starts from rest and moves a distance 13.0 m in a time 4.50 s. "
to solve for the block's acceleration, a.

X = (a/2)t^2
a = 2X/t^2

Using a, F = 79 N and F = m a, solve for m

The velocity when pushing stops at t = 4.5 s is
Vmax = a t

After 4.7 seconds, the additional distance traveled is Vmax*4.7 s

Answer 2

19