AP Physics 1 acceleration multiple choice questions and explanations

📚 Quick Study Guide

• 📏 Definition: Acceleration is the rate at which an object's velocity changes over time. It's a vector quantity, meaning it has both magnitude and direction.
• 🧮 Formula: Average acceleration ($a_{avg}$) is calculated as the change in velocity ($\Delta v$) divided by the change in time ($\Delta t$): $a_{avg} = \frac{\Delta v}{\Delta t} = \frac{v_f - v_i}{t_f - t_i}$, where $v_f$ is the final velocity and $v_i$ is the initial velocity.
• ⏱️ Units: The standard unit for acceleration is meters per second squared (m/s²).
• ➡️ Direction: Positive acceleration means the object is speeding up in the positive direction or slowing down in the negative direction. Negative acceleration (deceleration) means the object is slowing down in the positive direction or speeding up in the negative direction.
• 📉 Constant Acceleration: When acceleration is constant, we can use kinematic equations to relate displacement, initial velocity, final velocity, acceleration, and time. For example: $v_f = v_i + at$, $\Delta x = v_i t + \frac{1}{2} a t^2$, $v_f^2 = v_i^2 + 2 a \Delta x$.

🤔 Practice Quiz

1. A car accelerates from rest to 20 m/s in 5 seconds. What is its average acceleration?
   1. 4 m/s²
   2. 5 m/s²
   3. 10 m/s²
   4. 25 m/s²
2. A ball is thrown upwards with an initial velocity of 15 m/s. Assuming negligible air resistance, what is the acceleration of the ball at its highest point?
   1. 0 m/s²
   2. 9.8 m/s² downwards
   3. 9.8 m/s² upwards
   4. 15 m/s² downwards
3. An object moving with a velocity of 10 m/s experiences a constant acceleration of -2 m/s². How long will it take for the object to come to rest?
   1. 2 seconds
   2. 5 seconds
   3. 10 seconds
   4. 20 seconds
4. A cyclist accelerates from 5 m/s to 15 m/s over a distance of 50 meters. What is the cyclist's acceleration?
   1. 1 m/s²
   2. 2 m/s²
   3. 2.5 m/s²
   4. 4 m/s²
5. Which of the following is NOT a unit of acceleration?
   1. m/s²
   2. km/h/s
   3. m/s
   4. ft/s²
6. A rocket accelerates at a constant rate of 50 m/s² for 10 seconds. If its initial velocity is 0 m/s, what is its final velocity?
   1. 5 m/s
   2. 50 m/s
   3. 500 m/s
   4. 5000 m/s
7. A car traveling at a constant velocity suddenly brakes and comes to a stop in 4 seconds. If its initial velocity was 30 m/s, what was the car's acceleration during braking?
   1. -7.5 m/s²
   2. 7.5 m/s²
   3. 120 m/s²
   4. -120 m/s²