Answer to Question #160153 in Field Theory for Ange

Question

Briefly describe an experiment by which the value of g may be determined. Indicate the measurements taken and how to calculate the result.

Answer 1

Drop a ball from a measured height h; start and stop a timer to find t.

Students should be able to comment on the problems with starting and stopping the timer at the correct instants. Reaction time here is not the same as the human response to a random stimulus, since we can watch the ball falling and anticipate the correct moment to stop the timer. It’s still, however, a poor way to measure g!

Repeated measurements for a fixed value of h will give a range of values for t. Some students may be better at using a consistent technique, which will give a smaller spread in the values of t. This reduces the random error, but there may still be systematic error, which itself may be revealed by repeating the experiment for different values of h.

$$g=\frac{2h}{t^2}$$