Acceleration = a = ∆V/∆t; t = travel timeUniformly Accelerated Motion
Name:_________________________________ Date:__________ Time:_____________
Partners:________________________________ Course:________________
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Purpose: Study the motion of a cart down an air-track and investigate its acceleration and energy.
Apparatus: Air-track, cart, wood-block, vernier caliper, photogate timer, accessory photogate, meter stick, balance, and lab-jack.
Instructor will explain the following:
1. Introduction of the apparatus.
2. How to determine the angle of inclination of the track.
3. How to determine the instantaneous velocity, V of the cart at a position.
4. How to determine the travel-time, t using the photogate-timer and the accessory photogate.
5. Potential Energy (PE), Kinetic Energy (KE), and Mechanical Energy (ME). Website.
THEORY:
Instantaneous Velocity = V = ∆X/∆t
Acceleration = a = ∆V/∆t; t = travel time
Kinetic Energy = KE = ½Mv2
Potential Energy = PE = Mgh
Mechanical Energy (ME) consists of Kinetic energy and/or potential energy.
UNITS:
|
Time |
Mass |
Force |
Distance |
Velocity |
Acceleration |
Energy | |
|
cgs |
s |
g |
dyne |
cm |
cm/s |
cm/s2 |
erg |
|
SI |
s |
Kg |
Newton, N |
m |
m/s |
m/s2 |
Joule, J |
|
BE/USC |
s |
slug |
pound, lb |
foot, ft |
ft/s |
ft/s2 |
ft.lb |
cgs- centimeter, gram, second; SI-International System; BE/USC- British Engineering/US customary.
Procedure:
1. Set up the air-track on the
laboratory table.
2. What is the total marked length of the track? ________________
3. Incline the air-track using a wood block.
4. Determine the angle of inclination.
       |
5. Put the cart on the track, at the top. Write down the
starting position of the cart, using the front-edge of the card as
reference.__________________
6. Turn on the air-track and observe the motion of the cart.
7. What is accomplished by the air-flow.
8. Describe the motion of the cart.
9. About 15-cm down the track, pick a position, and measure the height. From the table-surface to the bottom-track.
10. At this position set up the photogate-timer to measure the short time, ∆t.
11. Let the cart slide down from the top, and measure ∆t.
12. Repeat 9-11, for 6 more positions down the track.
13. Set up the photogate-timer and the accessory photogate to measure the travel-time.
14. Measure the travel-time t from the starting position to the first position.
15. Repeat 14, for other positions.
DATA:
Width of the card on the cart = ∆x = _______m Mass of the cart, M = _________kg
| Position(m) | Height (m) | Short Time, ∆t (s) | Travel Time, t (s) |
16. Enter the above data in a spread sheet program and then calculate the following: Instantaneous Velocity (V), Potential Energy (PE), Kinetic Energy (KE), and Mechanical Energy (ME).
17. Plot Instantaneous Velocity (V) versus Travel Time (t) and determine the acceleration from the graph. Using this acceleration and the angle of inclination, determine the acceleration due to gravity, g.
18. Plot PE, KE, and ME versus Travel-Time(t), on the same graph.
19. Write a conclusion.