A 25-N crate slides down a frictionless incline that is 25° above the horizontal.The magnitude of the normal force of the incline on the crate is:
A)11 N
B)23 N
C)25 N
D)100 N
E)220 N

Question

Quizplus · Accepted Answer

The normal force can be found by using the formula $N = mg\cos(\theta)$, where $N$ is the normal force, $m$ is the mass of the object, $g$ is the acceleration due to gravity (9.8 m/s$^2$), and $\theta$ is the angle of the incline. Given that the weight of the crate is 25 N, we can find the mass $m = \frac{25}{9.8}$. Substituting the values, $N = \frac{25}{9.8} \times 9.8 \times \cos(25^\circ)$, which simplifies to $N = 25 \times \cos(25^\circ)$. Calculating this gives a value close to 23 N, making option B the correct answer.

A 25-N Crate Slides Down a Frictionless Incline That Is