Question

A child pushes a 31-kg shopping cart by a force of 120 N in a supermarket at angle of 25 degrees above the horizontal. If the cart experiences a friction force of 50 N that acts simultaneously on it, calculate the magnitude of its horizontal acceleration.
Bonus: Calculate the normal force acting on the cart.

Answer 1

$$ma=F\cos{25}-F_f$$

$$31a=120\cos{25}-50$$

$$a=1.9\frac{m}{s^2}$$

The normal force acting on the cart:

$$N=mg-F\sin{25}$$

$$N=(31)(9.8)-120\sin{25}=250\ N$$