How does horizontal motion affect the average acceleration of an object when there is air resistance?

1. Double-click on the environment to open its Property Box, make sure that Planet X is selected, and set the atmosphere to 40%.

2. Observe the height of the drop tower and make sure it is set to 1,000 meters.

3. Place the generic ball on the drop tower.

4. Double-click on the generic ball to open its Property Box and set the horizontal velocity to 10 m/s. Make sure the mass is set to 1.0 kg and the radius is 0.1 meters.

5. Double-click on each photogate to open its Property Box, select the generic ball from the Objects list, and record the photogate's vertical distance from the generic ball directly above it. (Hint: When you select a generic ball from the Objects list, a yellow box highlights the corresponding ball in the Lab Window.)

6. Click the Run button. After the ball hits the ground, click the Pause button.

7. Observe and record the times shown on each photogate.

8. Use the times on the photogates and the vertical distances of the photogates to calculate the average vertical velocities and average vertical acceleration for the generic ball. (Refer to the procedure in Experiment 2, Standard Setup 1, for information on calculating velocity and acceleration.)

9. Click the Stop/Reset button.

10. Double-click on the generic ball to open its Property Box and set the horizontal velocity to 50 m/s.

11. Click the Run button. After the ball hits the ground, click the Pause button.

12. Calculate the average vertical velocities and average vertical acceleration for the generic ball.

13. Calculate the percent difference in the average vertical acceleration between the two runs.

The percent difference is calculated by taking the difference between the average accelerations and dividing by the average of the two accelerations; for example, if A10 is the average acceleration at an initial horizontal velocity of 10 m/s and A50 is the average acceleration at an initial horizontal velocity of 50 m/s, then the percent difference equals [(A10 - A50) / (A50 + A10)/2] x 100.

To answer the questions pertaining to this experiment, click the Questions button.

EXPERIMENT 5: Horizontal and Vertical Motion in Air/

Standard Setup 1

Questions:

Select the best answer or the answer closest to your calculated value.

1. The average acceleration for a generic ball with an initial horizontal velocity of 10 m/s is closest to
a) 4.7 m/sec squared
b) 4.8 m/sec squared
c) 4.9 m/sec squared
d) 5.0 m/sec squared

2. The average acceleration for the generic ball with an initial horizontal velocity of 50 m/s is closest to
a) 4.7 m/sec squared
b) 4.8 m/sec squared
c) 4.9 m/sec squared
d) 5.0 m/sec squared

3. The percent difference in the average acceleration between the two runs is closest to
a) 3.1%
b) 5.3%
c) 6.8%
d) 7.6%

4. Increasing the initial horizontal velocity from 10 m/s to 50 m/s
a) increases the average vertical acceleration
b) decreases the average vertical acceleration
c) has no effect on the average vertical acceleration

5. Horizontal motion
a) affects the average vertical acceleration of an object in the presence of air resistance
b) does not affect the average vertical acceleration of an object in the presence of air resistance

6. Horizontal and vertical motion are
a) dependent in the presence of air resistance (affect each other)
b) independent in the presence of air resistance (do not affect each other)

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