Unknown Mass Challenge

Challenge: Find the mass of an object placed on a cart using the conservation of momentum principle. We used two carts, a can (unknown mass), and motion sensors. 

Procedure: First, we knew the mass of an empty cart was 0.5 kg. We then measured the velocity of the cart in order to find Va. After we measured the velocity of the first cart, we then measured the velocity of the second cart with the can (Vab).

Diagram:  

Data:                                                  

Velocity – Cart 1	Velocity – Cart 2
0.56 m/s	- 0.28 m/s
0.57 m/s	- 0.29 m/s
0.54 m/s	- 0.27 m/s
0.57 m/s	- 0.28 m/s
0.51 m/s	- 0.28 m/s
0.57 m/s	- 0.29 m/s

                                                         

Calculations:

 We then used the law of conservation of momentum to calculate the mass of the cart. Pi = Pf or mava + mbvb = (ma + mb)(vab)

We were 4.4% off when we tested our prediction which was around 500 kg and the actual mass was around 478 kg.