A boy (30 kg) sitting on his horse whips it. the horse speeds up at an average adcceleration of `2.0 m/s^2`. A. If the boy does not slide back, what is the force of friction exerted by the horse on the boy? b.If the boy slides back during the acceleration, what can be said about the coefficient of static friction between the horse and the boy.
`Take = 10 m/s^2`

Explanation

a. The forces acting on the boy are
i. the weight Mg
ii. the normal contact force N and
the static friction `f_s`.