Question

A child pulls a 22 kg sled with a force of 60 N on the sled at an angle of 20˚ above the horizontal, as shown in the figure above. The coefficient of kinetic friction between the sled and the surface is .22.

Answer 1

Suppose we need to find the acceleration of the sled.

$60\cdot\cos20°-0.22N=ma$

$N+60\cdot \sin20°=mg\to N=mg-60\cdot\sin20°=22\cdot 9.8-60\cdot\sin20°=195(N)$

$a=\frac{60\cdot\cos20°-0.22N}{m}=\frac{60\cdot\cos20°-0.22\cdot195}{22}=0.613(m/s^2)$. Answer