Question

A 1.8 kg otter starts from rest at the top of a

muddy incline 83.5 cm long and slides down

to the bottom in 0.50 s.

What net external force acts on the otter

along the incline?

Answer in units of N.

Answer 1

By the condition of the problem $s=AB=83.5sm=0.835m$

from the formula $s=\frac{at^2}{2}$ we determine the acceleration

$a=\frac{2s}{t^2}=\frac{2\cdot 0.835}{0.5^2}=6.68{m/s^2}$

then we write down Newton’s second law

$F=m \cdot a=1.8 \cdot 6.68=12.024N$