1.1. The symbol ‘g’ can be used to refer to the acceleration due to gravity.

The acceleration due to gravity ‘g’ has the unit of m/s².

‘g’ can also have another unit.

Which of these is also a unit for g ?

1.2. Two students try to determine a value for g, the acceleration due to gravity.

(i) They measure the time, t, for a small steel ball to fall through a height, h, from rest.

They measure t to be 0.74 s, using a stopwatch.

They measure h to be 2.50 m, using a metre rule.

Calculate a value for g from the students’ measurements.

Use the equation

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

                     g = .............................................................. m/s²(2)

(ii) They record the time t for two more drops from the same height.

The three values for time t are

0.74 s, 0.69 s, 0.81 s.

Calculate the average value of time t to an appropriate number of significant figures.

average value of time t = ........................................... s(2)

1.3. Explain one way the students could improve their procedure to obtain a more accurate value for g.

1.4. A car travelling at 15 m/s comes to rest in a distance of 14 m when the brakes are applied.

Calculate the deceleration of the car.

Use an equation selected from the list of equations at the end of this paper.

deceleration = ................................................ m/s²