Question

1. controlled variables (what will stay the same?):
2. hypothesis (if...then...):

part 3 - procedure (outline your steps)
write a numbered list of steps you will follow. must include:

• measuring the mass of the car (with or without added weights).
• launching the car with a spring force (1 n or 2 n).
• measuring the time to travel 1 meter.
• repeating trials.
• calculating acceleration.

steps:
1.
2.
3.

Explanation:

Step1: Identify controlled variables

The surface on which the car moves, the type of car (except for added - weights), the spring used for launching (assuming it's the same spring for all trials), and the distance of 1 meter for measurement should stay the same.

Step2: Formulate a hypothesis

If the spring force is increased from 1 N to 2 N while the mass of the car remains constant, then the time taken for the car to travel 1 meter will decrease and the acceleration will increase.

Step3: Outline the procedure steps

1. Use a balance to measure the mass of the car without added weights. Record the value.
2. Place the car on the flat surface. Compress the spring to apply a 1 N force and launch the car. Start a stop - watch as soon as the car is launched and stop it when the car travels 1 meter. Record the time.
3. Repeat step 2 for 5 trials with the 1 N spring force. Calculate the average time for the 1 N trials.
4. Add some weights to the car and measure the new mass.
5. Compress the spring to apply a 2 N force and launch the car (with the added weights). Start and stop the stop - watch as before and record the time. Repeat this for 5 trials with the 2 N spring force and calculate the average time.
6. Use the formula $a=\frac{2d}{t^{2}}$ (where $d = 1$ meter) to calculate the acceleration for both the 1 N and 2 N cases.

Answer:

Controlled Variables: Surface, type of car (except added - weights), spring, distance of 1 meter.
Hypothesis: If the spring force is increased from 1 N to 2 N while the mass of the car remains constant, then the time taken for the car to travel 1 meter will decrease and the acceleration will increase.
Procedure Steps:

1. Measure the mass of the car without added weights.
2. Launch the car with 1 N spring force and measure time for 1 - meter travel. Repeat 5 times.
3. Add weights to the car and measure new mass.
4. Launch the car with 2 N spring force and measure time for 1 - meter travel. Repeat 5 times.
5. Calculate acceleration for both force cases.