The method and the results are on the work-energy theorem lab. Do the analysis yourself first, then check the answers below.
Quick answer: Work is the energy a force transfers when it acts through a displacement: W = F d cosθ, in joules. These answers go with the AP Physics 1 lab on work-energy theorem: the graph, the calculations, the uncertainties and the conclusion explained, for all 7 analysis questions.
Here are the work-energy theorem lab answers for AP Physics 1: graph, calculations, uncertainties and conclusion. First do the lab yourself, then compare, and go back to the lesson if needed.
The sample data give a ratio close to one, as the theorem predicts. The model answers show the calculations, the shape of the graph and the main sources of error.
Level: AP Physics 1 (algebra-based) · Curriculum: AP P1 Unit 3
Work-energy theorem lab answers: the analysis explained
Question 1 Check one row
W = M g d = 0.050 × 9.81 × 0.60 = 0.294 J. K = ½ × (0.500 + 0.050) × 1.03² = 0.275 × 1.0609 = 0.292 J. Ratio = 0.292 ÷ 0.294 = 0.99.
Question 2 Why the total mass
The hanging mass moves at the same speed as the cart, so both carry kinetic energy. The work done by gravity on M is shared between them. Use m + M = 0.550 kg.
Question 3 Plotting
The points lie close to a straight line through the origin with a gradient near 1. K is proportional to W.
Question 4 Gradient
Gradient = ΣW·K ÷ ΣW² = 0.99. The theorem predicts 1.00, so the data support it within about 1 %.
Question 5 Percentage uncertainty
Percentage uncertainty in v = 0.02 ÷ 0.59 = 3.4 %. K depends on v², so double it: about 6.8 %.
Question 6 Friction effect
Friction would do negative work on the cart, so less than M g d would become kinetic energy. K ÷ W would be below 1, and the shortfall would grow with d.
Question 7 Improvement
Use several different hanging masses and a motion sensor that records the speed continuously, so each run gives many points of K against W. More data over a wider range.
