Physics Quiz: Part 6

An interactive quiz on Applied Dynamics Problems.

Fundamental Concepts Review

Free-Body Diagram (FBD): The essential first step. Represent the object as a dot and draw all forces acting ON it as labeled arrows pointing away.

  • Equilibrium: If $a=0$, then $\Sigma F = 0$. This means the forces are balanced in all directions: $\Sigma F_x = 0$ and $\Sigma F_y = 0$.
  • Inclined Planes: Tilt your axes! Resolve gravity into components parallel ($mg\sin\theta$) and perpendicular ($mg\cos\theta$) to the ramp.
  • Systems of Objects: Analyze the whole system ($\Sigma F_{ext} = m_{total}a$) to find acceleration. Then isolate one object to find internal forces (like tension).

Problem 1: Equilibrium with Angled Forces

Hard
DynamicsEquilibriumTensionVectors

A 10 kg sign ($g = 9.8 \text{ m/s}^2$) is suspended by two ropes. Rope 1 is at 30° to the horizontal, and Rope 2 is at 60° to the horizontal. What are the approximate tensions $T_1$ and $T_2$?

A

$T_1 = 98.0 \text{ N}, T_2 = 98.0 \text{ N}$

B

$T_1 = 84.9 \text{ N}, T_2 = 49.0 \text{ N}$

C

$T_1 = 49.0 \text{ N}, T_2 = 84.9 \text{ N}$

D

$T_1 = 56.6 \text{ N}, T_2 = 56.6 \text{ N}$