Stopping Distance
Stopping Distance
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When a person drives a car and sees a hazard, they need to apply brakes to stop as fast as they can.
The DISTANCE they travel from the moment they PRESS THE BRAKES to the moment they STOP is known as the STOPPING DISTANCE.
The STOPPING DISTANCE of a vehicle is the SUM of TWO distances:
1. THINKING DISTANCE - This is the DISTANCE the vehicle travels during the DRIVER'S REACTION TIME, between the time the driver sees a hazard and the time they start to brake.
2. BRAKING DISTANCE - This is the DISTANCE the vehicle travels while the BRAKES ARE APPLIED.
For a given braking force the GREATER the SPEED of the vehicle, the GREATER the STOPPING DISTANCE.
This is because increasing the SPEED of the car increases BOTH the thinking distance AND the braking distance.
The THINKING DISTANCE of a car is based on the REACTION TIMES of the driver.
The longer the driver’s reaction time, the LONGER the THINKING DISTANCE.
The average human reaction time is around 0.2s – 0.9s.
There are a few factors that can INCREASE a person’s reaction time:
You can measure a person’s reaction time by using tests on the computer:
These tests often involve responding to a visual change, like a color shift on the screen, by pressing a key or clicking the mouse as fast as possible.
The braking distance of a vehicle is the distance it travels when the brakes are applied to bring it to a complete stop. Several factors can affect a vehicle's braking distance, which are:
When a force is applied to the brakes of a vehicle, WORK is DONE by the FRICTIONAL force between the brakes and the wheel.
This REDUCES the KINETIC ENERGY of the vehicle as it is TRANSFERRED to the THERMAL ENERGY stores of the brakes.
This causes the TEMPERATURE of the brakes to INCREASE.
This transfer of energy causes the car to DECELERATE (slow down).
The GREATER the speed of a vehicle, the GREATER the braking force required to bring the vehicle to a STOP for a given distance.
Since the BRAKING FORCE would need to be LARGER, the DECELERATION of the vehicle will be LARGE as well.
This is because the RESULTANT force of the car will be GREATER, leading to a GREATER DECELERATION (Newton's Second Law).
LARGE DECELERATIONS are dangerous as they could lead to the brakes OVERHEATING and a LOSS OF CONTROL of the vehicle.
When a person drives a car and sees a hazard, they need to apply brakes to stop as fast as they can.
The DISTANCE they travel from the moment they PRESS THE BRAKES to the moment they STOP is known as the STOPPING DISTANCE.
The STOPPING DISTANCE of a vehicle is the SUM of TWO distances:
1. THINKING DISTANCE - This is the DISTANCE the vehicle travels during the DRIVER'S REACTION TIME, between the time the driver sees a hazard and the time they start to brake.
2. BRAKING DISTANCE - This is the DISTANCE the vehicle travels while the BRAKES ARE APPLIED.
For a given braking force the GREATER the SPEED of the vehicle, the GREATER the STOPPING DISTANCE.
This is because increasing the SPEED of the car increases BOTH the thinking distance AND the braking distance.
The THINKING DISTANCE of a car is based on the REACTION TIMES of the driver.
The longer the driver’s reaction time, the LONGER the THINKING DISTANCE.
The average human reaction time is around 0.2s – 0.9s.
There are a few factors that can INCREASE a person’s reaction time:
You can measure a person’s reaction time by using tests on the computer:
These tests often involve responding to a visual change, like a color shift on the screen, by pressing a key or clicking the mouse as fast as possible.
The braking distance of a vehicle is the distance it travels when the brakes are applied to bring it to a complete stop. Several factors can affect a vehicle's braking distance, which are:
When a force is applied to the brakes of a vehicle, WORK is DONE by the FRICTIONAL force between the brakes and the wheel.
This REDUCES the KINETIC ENERGY of the vehicle as it is TRANSFERRED to the THERMAL ENERGY stores of the brakes.
This causes the TEMPERATURE of the brakes to INCREASE.
This transfer of energy causes the car to DECELERATE (slow down).
The GREATER the speed of a vehicle, the GREATER the braking force required to bring the vehicle to a STOP for a given distance.
Since the BRAKING FORCE would need to be LARGER, the DECELERATION of the vehicle will be LARGE as well.
This is because the RESULTANT force of the car will be GREATER, leading to a GREATER DECELERATION (Newton's Second Law).
LARGE DECELERATIONS are dangerous as they could lead to the brakes OVERHEATING and a LOSS OF CONTROL of the vehicle.
