A rope holds a 25-kg rock at rest on a frictionless inclined plane as shown. Determine the tension in the rope.

ANSWER:
122.5 N
STEP-BY-STEP EXPLANATION:
In order to determine the tension, we must make a force diagram of the situation, like this
We can see that the tension is equal to the x-component of the weight, therefore:
[tex]\begin{gathered} T=W_x \\ \\ W_x=mg\cdot\sin\theta \\ \\ T=25\cdot9.8\sin30\degree \\ \\ T=122.5\text{ N} \end{gathered}[/tex]Therefore, the tension is equal to 122.5 newtons