Investigating Forces
Plan and carry out investigations into forces, including measuring force with a newton meter, investigating Hooke's Law, and collecting and interpreting motion data to test Newton's laws
What a learner can do afterwards
- Uses a newton meter correctly to measure forces in newtons
- Sets up and conducts a Hooke's Law investigation, recording force and extension and plotting a graph
- Identifies and controls variables in a force investigation
- Calculates acceleration from force and mass data and compares with experimental results
The lesson
You've already used a spring to explore Hooke's Law. Now it's time to run your own investigation properly, starting with the right tool to measure force. A newton meter measures force in newtons. Hook it onto the object, pull steadily in a straight line, and read the scale at eye level so your measurement is accurate.
Priya investigates how force affects a trolley's acceleration. She keeps the trolley's mass the same every time and only changes the force she applies with a newton meter, recording the resulting acceleration from motion sensors. Because she changes just one variable, she can be sure the force, and nothing else, caused any change in acceleration.
Change only one variable at a time and keep everything else the same. Repeat each reading at least twice, and hold the newton meter at eye level, in line with the direction of motion, so your results are reliable.
Once you have your data, use F = ma to calculate the acceleration you'd expect. Compare it with what your motion sensors actually measured. If the numbers don't quite match, look for forces you didn't control, like friction, rather than assuming your maths is wrong.
Measure force accurately with a newton meter, change one variable at a time, plot your force and extension data, then compare your calculated acceleration with what you actually measured.
Watch it
Where it sits
This opens up
Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.