Equipment used
Fundamental : Apparatus used to measure g Equipment used
Apparatus:
Metre rule
ball bearing
electromagnet
electronic timer
trapdoor
The experiment goes through five stages:
When the current to the magnet switches off, the ball drops and the timer starts
When the ball hits the trapdoor, the timer stops
The reading on the timer indicates the time it takes for the ball to fall a distance, h
This procedure is repeated several times for different values of h, in order to reduce random error
The distance, h, can be measured using a metre rule, in this practical work we use the distances between 20 cm – 1 m
Analysing data
To find g , use the same steps as in the problem solving section
The known quantities are
Time taken = t
Initial velocity u = 0
Acceleration a = g
The equation that links these quantities is
s = ut + ½ at2
h = ½ gt2
Using this equation, deduce g from the gradient of the graph of h against t2