AP Physics 1 Questions on Work Done by a Constant Force

📚 Quick Study Guide

• 🏋️ Work is done when a force causes a displacement.
• 📐 The work done by a constant force is given by $W = Fd\cos(\theta)$, where $F$ is the magnitude of the force, $d$ is the magnitude of the displacement, and $\theta$ is the angle between the force and displacement vectors.
• ➕ Work is a scalar quantity; it can be positive (force aids the motion), negative (force opposes the motion), or zero (force is perpendicular to the motion).
• 📏 The SI unit of work is the joule (J), where 1 J = 1 N·m.
• 💡 When multiple forces act on an object, the net work done is the algebraic sum of the work done by each individual force, or the work done by the net force.
• 🛤️ If the force is in the same direction as the displacement, then $W = Fd$.
• 🚫 If the force is perpendicular to the displacement, then $W = 0$.

🧪 Practice Quiz

1. A box is pulled 5 meters along a horizontal floor with a force of 10 N applied at an angle of 30 degrees above the horizontal. How much work is done by the force?
   1. 43.3 J
   2. 50 J
   3. 86.6 J
   4. 0 J
2. A 2 kg book is lifted vertically 1.5 meters. What is the work done by gravity on the book?
   1. 29.4 J
   2. -29.4 J
   3. 0 J
   4. 3.0 J
3. A car travels 20 meters while a constant friction force of 500 N acts on it, opposing its motion. How much work is done by friction?
   1. 10,000 J
   2. -10,000 J
   3. 0 J
   4. 25 J
4. A block is pushed horizontally with a force of 20 N across a frictionless surface for a distance of 3 meters. How much work is done?
   1. 60 J
   2. 0 J
   3. 20 J
   4. 3 J
5. A person carries a 10 kg backpack horizontally across a distance of 100 meters. How much work is done by the person on the backpack?
   1. 9800 J
   2. 0 J
   3. 98 J
   4. 1000 J
6. A force of 50 N is applied at an angle of 60 degrees to pull a sled 10 meters. Calculate the work done.
   1. 250 J
   2. 433 J
   3. 500 J
   4. 0 J
7. A constant force of 30 N acts on an object in the same direction as its displacement of 6 meters. Determine the work done.
   1. 180 J
   2. 5 J
   3. 0 J
   4. 36 J