Force --- Suggested Experiments

Explanation of Newton's second law of motion
Explanation of Newton's third law of motion

Explanation of Newton's second law of motion
Tilt the runway at an angle such that a trolley will move down the runway with uniform velocity when slightly pushed. In this way, the runway is friction-compensated. Pull the trolley down the runway with an elastic cord stretched to the same length as the trolley. Label the tape as 1. Repeat with two cords in parallel. Label the tape as 2. Repeat with two cords connected to two trolleys. Label the tape as 3.
One stretched cord connected to one trolley causes the same acceleration as two stretched cords connected to two trolleys. Two stretched cors connected to one trolley causes a greater acceleration than one stretched cord connectd to one trolley.
To be quantitative, we may measure the acceleration for each tape by constructing a tape chart. It is found that the acceleration for tape 2 is twice that for tape 1 and tape 3. In this experiment all elastic cords are stretched by the same amount. there force, two stretched cords set up twice the elastic force as one stretched cord. In addition, the mass of two trolleys is obviously twice that of one trolley.
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Explanation of Newton's third law of motion
Push the toy car several times on the bench. Then place it on the cardboard above a think layer of polystyrene. The toy car moves forward due to an action exerted on the wheels by the cardboard. The cardboard moves backwards due to a reaction exerted on the cardboard by the wheels. The two forces act in opposite directions.
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Friction Force of Gravity Newton's Laws of Motion Suggested Experiments