What is the formula for stopping distances??
$$ \text{stopping distance} = \text{thinking distance} + \text{braking distance} $$
What affects reaction time in the context of stopping distances??
- Tiredness
- Alcohol
- Drugs
- Other passengers
What are the two factors that affect stopping distance??
- Reaction time
- Speed of the vehicle
Assuming a constant velocity ($v$) during reaction time, what is the formula for thinking distance??
$$ s = vt $$
What are the three factors that affect braking distance??
- Breaking force
- Mass of vehicle
- Velocity
What things can affect the breaking force??
- Break conditions
- Tire conditions
- Road conditions
A larger vehicle mass has what affect on braking distance??
A larger breaking distance.
When a car is in motion, what’s the kinetic energy of the car??
$$ \frac{1}{2} m v^2 $$
Where is the kinetic energy of a car transferred to when braking??
Transferred to the thermal store of the breaks and the surroundings.
What is the work done by a car when it’s breaking??
$$ W = F \times s $$
When a car is breaking and the energy is being calculated by $W = F \times s$, what does $F$ represent??
The breaking force of the car.
What are the units for work done??
joules, $J$
What must be true about the kinetic energy of a car and the work done when breaking??
They must be equal.
What is the formula for the kinetic energy of a car in relation to work done??
$$ \frac{1}{2} m v^2 = F \times s $$
What is the formula for breaking distance involving mass, velocity and breaking force??
$$ \frac{1}{2} m v^2 = F \times s $$
What is the formula for breaking distance involving velocity and acceleration??
$$ \text{breaking distance} = \frac{(initial velocity)^2}{2 \times \text{acceleration}} $$
What does a $2\times$ initial velocity translate to in terms of breaking distance??
$4\times$ the breaking distance.
The breaking distance equation involving velocity and acceleration is a special case of which SUVAT equation??
$$ v^2 = u^2 + 2as $$
If a truck is exerts a breaking force of $8700N$ and has a mass of $2300kg$, how could you calculate the acceleration??
$$ \text{8700N}{2300kg} \\ F = ma $$
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date: 2020-10-08 17:33
tags:
- '@?physics'
- '@?year-1'
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- '@?public'
title: Physics - Stopping Distances