Equilibrium Quiz with Answers: Test Your AP Physics 1 Knowledge

📚 Quick Study Guide

• ⚖️ Equilibrium occurs when the net force and net torque on an object are zero.
• $\\sum F = 0$ (The sum of all forces equals zero).
• $\\sum \\tau = 0$ (The sum of all torques equals zero).
• 📏 Torque ($\\tau$) is calculated as the product of the force ($F$) and the lever arm ($r$): $\\tau = rFsin(\\theta)$.
• 📐 The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force.
• 🔑 Types of Equilibrium:
  • Static Equilibrium: Object is at rest.
  • Dynamic Equilibrium: Object is moving with constant velocity.
• 💡 Remember to consider all forces acting on the object, including gravity, tension, normal force, and friction.

🧪 Practice Quiz

1. A uniform beam of weight $W$ is supported by two ropes at its ends. If the tension in one rope is $T_1 = \\frac{2}{3}W$, what is the tension $T_2$ in the other rope?
   1. $\frac{1}{3}W$
   2. $\frac{1}{2}W$
   3. $\\frac{2}{3}W$
   4. $W$
2. A ladder leans against a smooth wall. The ground is not frictionless. What forces act on the ladder?
   1. Weight, normal force from the wall, normal force from the ground.
   2. Weight, normal force from the wall, friction from the ground.
   3. Weight, normal force from the ground, friction from the ground.
   4. Weight, normal force from the wall, normal force from the ground, friction from the ground.
3. A sign of weight $100 N$ is hanging from two ropes that make an angle of $30^\\circ$ with the horizontal. What is the tension in each rope?
   1. $50 N$
   2. $100 N$
   3. $57.7 N$
   4. $115.5 N$
4. A meter stick is pivoted at the 50 cm mark. A weight of $5 N$ is hung at the 20 cm mark. Where should a weight of $10 N$ be hung to balance the meter stick?
   1. 65 cm
   2. 80 cm
   3. 30 cm
   4. 20 cm
5. A car is parked on a hill. Which of the following statements is true regarding the forces acting on the car?
   1. The normal force is equal to the weight of the car.
   2. The friction force is equal to the component of the weight parallel to the hill.
   3. The friction force is equal to the weight of the car.
   4. There is no friction force acting on the car.
6. A seesaw is balanced with a child on each end. If one child moves closer to the center, what happens?
   1. The seesaw remains balanced.
   2. The other child's side goes down.
   3. The child who moved closer to the center's side goes down.
   4. The seesaw starts to rotate.
7. A bridge is supported by two pillars. A truck is at the center of the bridge. What is the force exerted by each pillar?
   1. Equal to the weight of the truck.
   2. Half the weight of the truck.
   3. Dependent on the length of the bridge.
   4. Zero.