Required Practical: Investigating Force & Acceleration (OCR GCSE Physics A (Gateway Science Suite)): Revision Notes

Setup

1. Draw several straight lines at equal intervals perpendicular to the edge of a bench using chalk. These will help you measure the car's movement.
2. Attach a toy car to a piece of string. Place the string over a pulley at the end of the bench.
3. Attach a weight stack to the loose end of the string. Hold the weight stack so it doesn't pull the car but keeps the string fully extended.
4. When ready, release the weight stack and start the timer.
5. Stop the timer when the car reaches the pulley at the other end of the bench.

Investigations 6. How Varying the Force Affects Acceleration with Constant Mass

• Start by adding a 10g mass to the weight stack. Hold the weights so they don't pull the car yet, but ensure the string remains fully extended.
• Release the weights and time how long it takes for the car to travel across the bench.
• Repeat this experiment, adding 10g weights each time and recording the travel time for each trial.

1. How Varying the Mass of the Car Affects Acceleration with a Constant Force

• Attach a 10g mass on top of the toy car using rubber bands or adhesive putty.
• Pull the car back to the starting chalk line and release it.
• Time how long it takes for the car to travel across the bench.
• Repeat the experiment by increasing the mass of the car and recording the time taken.

Calculation

• To calculate the acceleration, use the formula: $a= \frac{(vf−vi)t}{t}$ where:

• $a$ is the acceleration,

• $vf$ is the final velocity,

• $vi$ is the initial velocity (which is 0 if starting from rest),

• $t$ is the time taken. This setup helps explore how force and mass affect acceleration, reinforcing Newton's Second Law of Motion.