A 1.9 kg otter starts from rest at the top of a muddy incline 84.1 cm long and slides down to the bottom in 0.60 s.

What net external force acts on the otter along the incline?
Answer in units of N.

1 answer

d = 0.5at^2 = 0.841m.

0.5a(0.6)^2 = 0.841,
0.18a = 0.841,
a = 0.841 / 0.18 = 4.67.2m/s^2.

F = ma = 1.9 * 4.67 = 8.88N.