Physics - Galileo's Slope Experiment
OCR A-Level Physics 2022
Kinematics and Galileo’s prediction
What is kinematics?
Analysing the motion of an object (without caring about what causes the motion).
Why would $10.1 \pm 0.5ms^{-2}$ be an acceptable value for $g$?
Because the actual value of $g$ is $9.81ms^{-2}$, so the result is within the range of uncertainty.
What did Galileo predict about the motion of a falling object?
That its acceleration is uniform.
Velocity of a falling object
The slope experiment and its difficulties
What were the two problems Galileo’s encountered with the slope experiment?
- He didn’t have an accurate stopwatch
- No way to measure instantaneous velocity, only average velocity.
Why was not having an accurate stopwatch a difficulty for Galileo?
Because the object would fall too quickly, there would be too much error in the results.
What was Galileo’s solution to not having an accurate stopwatch?
Rolling the object down a slope instead of a having a straight drop.
Why was not knowing the average velocity enough in the slope experiment?
Galileo needs to know the instantaneous velocity to work out how the acceleration changes.
What was Galileo’s solution to not knowing the instantaneous velocity?
- By showing $s \propto t^2$ instead.
Why is $s \propto t^2$ the same as showing $v \propto t$?
- $v = at$
- $s = vt$
- $s = (at)t$
- $s = at^2$
- $s \propto t^2$
What was measured and concluded
What did Galileo measure in his experiment?
The time taken to reach multiple points on the slope.
Proving acceleration is uniform is the same as what observation made about a distance time graph?
The gradient is constant.
Which famous experiment determined the acceleration of free fall by rolling objects down an inclined plane?
Galileo’s Slope Experiment.