Question

A stone tablet of 6 kg on a 30° incline is held by a force of 5 N up and parallel to the incline. If the coefficient of kinetic friction between block and incline is 0.1

Solve for the tablet's acceleration.

Draw a representative figure.

Answer 1

Let's apply the Newton's Second Law of Motion:

$$F_p-mgsin\theta-F_{fr}=ma,$$ $$F_p-mgsin\theta-\mu_kmgcos\theta=ma,$$ $$a=\dfrac{F_p-mg(\mu_kcos\theta+sin\theta)}{m},$$ $$a=\dfrac{5\ N-6\ kg\cdot9.8\ \dfrac{m}{s^2}\cdot(0.1\cdot cos30^{\circ}+sin30^{\circ})}{6\ kg},$$ $$a=-4.91\ \dfrac{m}{s^2}.$$