6 (a) The symbol 'g' can be used to refer to the acceleration due to gravity - Edexcel - GCSE Physics - Question 6 - 2018 - Paper 1

To find the average time t, use the formula:

$t_{avg} = \frac{t_1 + t_2 + t_3}{3}$

Substituting the values:

$t_{avg} = \frac{0.74 + 0.69 + 0.81}{3} = \frac{2.24}{3} \approx 0.747$

Thus, the average value of time t is approximately 0.75 s when rounded to two significant figures.

One way to improve the procedure is by increasing the number of drops and averaging the results. More data points would help to minimize random errors and give a more precise average value of g.

To find the deceleration (a) of the car, we can use the equation:

$v^2 = u^2 + 2as$

Where:

• v = final velocity = 0 m/s (the car comes to rest)
• u = initial velocity = 15 m/s
• s = distance = 14 m

Rearranging the equation gives:

$a = \frac{v^2 - u^2}{2s}$

Substituting the values:

$a = \frac{0^2 - 15^2}{2 \times 14} = \frac{-225}{28} \approx -8.04$

Thus, the deceleration of the car is approximately -8.04 m/s².