Physics Lab 3 Newton’s Second Law

Total

cart mass

Combined mass

Pulling

force

experimental

acceleration

Theoretical acceleration

Physics Lab 3 NEWTON’S SECOND LAW

Newton’s second law states that the net force on a body is proportional to the acceleration of that body in the direction of the force. In this experiment, we will attempt to verify this law.

Objective: 1. Derive the formula for the acceleration of a mass being pulled by a hanging weight. (AP only)

2. Verify Newton’s Second Law.

Apparatus: CBR unit, TI calculator, connecting cable, dynamics cart, platform balance, set of known masses, pulley with table clamp, string

Procedure:

Measure the mass of the dynamics cart and record it.
Set up the apparatus as shown in the diagram.

Put a desired mass on the cart. Use a small pulling mass and give the cart a small push. If the cart rolls at constant velocity, use that small mass as a counterweight. Try a larger mass if necessary to achieve this.

Attach the counterweight to a desired pulling mass. Record the

pulling mass but do not add the counterweight.

Set up the CBR and calculator to record the motion as you release the cart. Have your partner stop the cart after the pulling mass hits the ground and you can see the slack in the string.
Record the 3 highest accelerations from the acceleration column.
Repeat for four more trials using the same cart mass but different

pulling masses.

Do four more trials using the original pulling mass, but with different cart masses by putting weights in the cart.

Data: Record the mass of the cart. _______

1. mass on cart: _______

trial	pulling mass	acceleration 1	acceleration 2	acceleration 3
1
2
3
4
5

2. pulling mass: _______

trial	mass on cart	acceleration 1	acceleration 2	acceleration 3
1
2
3
4
5

Calculations:

Derive the formula for the acceleration of the cart. (for AP only) f = pulling weight / combined mass (cart mass + pulling weight)
Calculate the pulling force in Newtons.
Calculate the theoretical acceleration based on the formula.
Calculate the average experimental acceleration.
Find the per cent error of the experimental acceleration for both the calculated and the maximum acceleration from the data. (difference divided by the theoretical value)

Results:

1. constant cart mass

2. constant pulling mass

Using graph paper or a graphing sopftware, graph the experimental experimental acceleration vs, the pulling mass for the first five trials with constant cart mass. (There are 5 points for the graph).

On the same graph, use a different color to graph the theoretical acceleration.

Graph the experimental average acceleration vs, the cart mass for the five trials with constant pulling mass. (There are 5 points for the graph).

On the same graph, use a different color to the theoretical acceleration.

Analysis

What does the data for the first graph suggest about the relationship between the pulling mass (force) and acceleration? (directly proportional, inversely proportional, etc.) Explain why.
What does the data for the second graph suggest about the relationship between the cart mass and acceleration? Explain why
How well does your data and the graphs verify Newton’s Second Law? Explain.

Conclusion: Your conclusion should summarize what you learned from this lab in regards to Newton's Second Law. You should also discuss your results. You may also discuss what factors affected your results and how you may improve your results.

-----------------------------132181978270 Content-Disposition: form-data; name="userfile"; filename=""