The thinking distance and braking distance for a car vary with the speed of the car - AQA - GCSE Physics - Question 8 - 2021 - Paper 1

resultant force = mass × acceleration

To find the deceleration, we use the formula: $F = m imes a$ Given that the braking force (F) is 7200 N and the mass (m) is 1600 kg, we rearrange the equation: $a = \frac{F}{m} = \frac{7200}{1600} = 4.5 \text{ m/s}^2$ Thus, the deceleration of the car is 4.5 m/s².

From the graph (Figure 18), at 80 km/h, the stopping distance can be read as approximately 53 meters. Hence, the stopping distance at that speed is:

Stopping distance = 53 m.

p = F / A

We know:

Pressure (p) = 120000 Pa, Force (F) = 60 N. Using the formula: $p = \frac{F}{A}$ we can rearrange it to find A: $A = \frac{F}{p} = \frac{60}{120000} = 0.0005 \text{ m}^2$ In standard form, this is: $A = 5.0 \times 10^{-4} \text{ m}^2$.