Question

Weigh the cart, hanger, and three 20-g masses together and record the value in the table below.

Weigh the hanger and a single 20-g mass, then the hanger and two 20-g masses, and finally the hanger and three 20-g masses, and record the values in the table below. You will need these values for your calculations after you have taken data.

Item	Mass (kg)
Total mass of the cart, hanger, and three 20-g masses (mtotal)	0.532
Total mass of the hanger and one 20-g mass	0.027
Total mass of the hanger and two 20-g masses	0.047
Total mass of the hanger and three 20-g masses	0.069

Run #1:

With two 20-g masses on the cart and one on the hanger, pull the cart 25 cm back from the end stop.

Click 'Start'. Release the cart. Stop the cart before it hits the pulley and click 'Stop'.

Run #2:

Move one of the 20-g masses from the cart to the hanger. Pull the cart 25 cm back from the end stop.

Click 'Start'. Release the cart. Stop the cart before it hits the pulley and click 'Stop'.

Run #3:

Move another of the 20-g masses from the cart to the hanger (all three masses should now be on the hanger). Pull the cart 25 cm back from the end stop.

Click 'Start'. Release the cart. Stop the cart before it hits the pulley and click 'Stop'.

Using Capstone the students obtained the following experimental acceleration for each run.

Run	Acceleration aexp (m/s2)
#1	0.258
#2	0.695
#3	0.90

For runs #1, #2, #3, the total mass of the system (mass of cart plus mass of hanger) is constant and the net force (mass of hanger × 9.8) increases. Record the mass and the net force, F_net, in the table below

•	Assuming no friction, the net force is the weight of the hanger (mass × 9.8 m/s2).

Run	Masses + hanger (kg)	Masses + cart (kg)	Fnet (N)
#1	FIND	FIND	FIND
#2	FIND	FIND	FIND
#3	FIND	FIND	FIND

Calculate the theoretical acceleration, a_th, when the mass is constant and the net force is changed and record the calculations in the table below.

•	The acceleration is the ratio of the net force divided by the total mass.

a_th =

F_net

m_cart + m_hanger

Find the percent error between the theoretical and experimental acceleration and record it in the table below.

Run	ath (m/s2)	aexp (m/s2)	% error (%)
#1	FIND	FIND	FIND
#2	FIND	FIND	FIND
#3	FIND	FIND	FIND

Answer 1