Investigating F = ma and evaluating evidence
≈ 48 minInvestigating F = ma and evaluating evidence
An investigation of Newton's second law needs a clear question and fair comparison. To test how net force affects acceleration, keep total mass approximately constant, vary net force in measured steps and measure acceleration using a motion sensor, ticker timer or velocity-time gradient. To test how mass affects acceleration, keep net force constant and vary total mass. Distinguish the independent variable you deliberately change, the dependent variable you measure and control variables that could otherwise affect acceleration, such as track angle, friction and timing method. A graph can support proportionality only after you examine scatter, uncertainty and whether the chosen axes match the proposed model.
Work it through
A 2.0 kg trolley experiences net force 4.0 N, predicting a = F/m = 2.0 m s⁻². If measured acceleration is lower, check friction, angle, force-sensor zero, moving mass and timing before rejecting the law. A strong conclusion names both the observed trend and a possible limitation, rather than claiming a few points prove every situation.
Mastery target
Design or evaluate a fair F = ma investigation, calculate a prediction, read its graph and communicate a conclusion with evidence and limitation.
In an investigation of how net force affects acceleration, what should be kept approximately constant?
Name the key physics term from Investigating F = ma and evaluating evidence that best fits the explanation and visual model.
A 2.0 kg trolley experiences net force 4.0 N. What acceleration in m s⁻² does F = ma predict?
Which statement corrects a common misunderstanding in Investigating F = ma and evaluating evidence?