Speed and Acceleration Lab



Speed and Acceleration Lab Name:_____________________

Problem: What factors and forces affect the speed and acceleration of a moving object?

Gathered Data:

• Speed is the distance an object travels per unit of time. Speed can be expressed as kilometers per hour (km/hr), meters per second (m/s), and so on. In most cases, objects don’t travel at a constant speed. Therefore, the average speed is used to describe the motion.

[pic]s = speed, t = time, and d = distance

• Acceleration is the rate at which an object’s speed changes. Acceleration can be expressed as meters per second per second (m/s/s or m/s2). Forces such as gravity, air resistance, and friction can cause an object to decelerate (decrease speed over time). Other forces can cause and object to accelerate (increase speed over time). If the car does not encounter these forces and travels at a constant speed, then it is not changing speed and there is no acceleration or deceleration.

[pic]a = acceleration, v = change in velocity or speed, and t = time

v = final velocity or speed – initial velocity or speed

Hypothesis:

What will be the average speed of a tennis ball rolling down a 20cm tall ramp and traveling 5m?

Will the ball continually accelerate as it travels the 5m? Or will it decelerate?

Experiment:

Materials- stack of books, wood ramp (shelf from cabinet), masking tape, stopwatch or watch with second hand, meter stick, pen or pencil, and tennis ball

Procedure-

1. Set up a 5m runway with a ramp at one end that raises 20cm. Be sure to smooth the ramp transition with the runway with a taped firm piece of paper.

2. Place a masking taper marker where the ramp touches the floor and label 0m. Label also 1m, 2m, 3m, 4m, and 5m markers from the start of the ramp.

3. Take a practice run with your tennis ball. Launch it from the top of the ramp and begin timing it at the 0m mark.

You will need to take enough trial runs to get timing measurements for the following distances: 0m to 1m, 0m to 2m, 0m to 3m, 0m to 4m, and 0m to 5m

4. Record your time data below

a. 0m to 1m ____________

b. 0m to 2m ____________

c. 0m to 3m ____________

d. 0m to 4m ____________

e. 0m to 5m ____________

Analysis:

5. Calculate the instantaneous speed at the following distances

f. 1m ____________ (1/a)

g. 2m ____________ (2/b)

h. 3m ____________ (3/c)

i. 4m ____________ (4/d)

j. 5m ____________ (5/e)

6. Calculate the time between each of the following distances

k. 1m to 2m ____________ (b – a)

l. 2m to 3m ____________ (c- b)

m. 3m to 4m ____________ (d – c)

n. 4m to 5m ____________ (e – d)

7. Calculate the acceleration for the following distances

o. 1m to 3m ____________ (h – f/k + l)

p. 2m to 4m ____________ (i – g/l + m)

q. 3m to 5m ____________ (j - h/m + n)

8. Line graph the instantaneous speed (f through j) and the average speed 0 – 5m; there will be two lines on your graph.

Conclusion:

1. Look at your hypothesis. Address each question as whether your guesses were true or false and how close you were.

2. Draw a diagram showing the exact path of each trial. Be detailed as to the exact points the ball might have curved in its path.

3. Did your ball travel at a constant speed? How do you know?

4. How could you change the experiment to make the ball decelerate faster?

5. How could you change the experiment to make the ball accelerate faster?

6. How could you change the experiment to make the ball not accelerate or decelerate for an entire 5m?

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