The method and the results are on the Newton's laws lab. Do the analysis yourself first, then check the answers below.
Quick answer: Newton's laws link force and motion. The first law says zero net force means constant velocity, the second says ΣF = ma, and the third says forces come in equal and opposite pairs acting on different objects. These answers go with the AP Physics 1 lab on Newton's laws: the graph, the calculations, the uncertainties and the conclusion explained, for all 7 analysis questions.
The model answers use the sample table. Your own values will differ a little, but the line should be straight with a gradient close to 1 ÷ M and a small intercept on the force axis.
Level: AP Physics 1 (algebra-based) · Curriculum: AP P1 Unit 2
From d = ½at² with u = 0, a = 2d ÷ t². For 0.060 kg: a = 2.00 ÷ 1.48² = 2.00 ÷ 2.19 = 0.91 m/s².
Question 2 The graph
Gradient = (1.57 − 0.26) ÷ (0.981 − 0.196) = 1.31 ÷ 0.785 = 1.7 m/s² per N.
Question 3 System mass
Gradient = 1 ÷ M, so M = 1 ÷ 1.67 = 0.60 kg, in agreement with the value found with the balance.
Question 4 The intercept
Extend the line: a = 0 when F = 0.196 − 0.26 ÷ 1.67 = 0.04 N. This is the friction force opposing the motion; only the force beyond 0.04 N accelerates the system.
Question 5 Constant total mass
Keeping M constant means that a changes only because F changes; adding mass to the hanger alone would raise F and M together, so a would not be proportional to F. Keeping M fixed at 0.600 kg makes the graph a straight line.
Question 6 String tension
For the hanger, mg − T = ma, so T = 0.100 × (9.81 − 1.57) = 0.82 N. This is smaller than the weight of 0.98 N because the hanger accelerates downward.
Question 7 Improvement
Use a low-friction track or an air track and a light pulley; use two photogates or a video to time the motion more precisely; time over a longer distance; repeat more times. The most effective change is photogate timing.
