Energy and Momentum Flashcards
What is the stopping distance?
The sum of the thinking and braking distances.
What is thinking distance affected by?
- Speed
2. Alertness
What is thinking distance?
The distance the vehicle travels during the driver’s reaction time.
What is braking distance affected by?
- Speed
- Brakes
- Tyres
- Grip
What is breaking distance?
The distance the vehicle travels under the braking force.
What is work?
When a force moves an object through a distance, work is done and energy is transferred.
What is work measured in?
Joules, J.
What is the formula for work?
Work done = force x distance
J = N x m
What is gravitational potential energy?
Energy due to vertical position in a gravitational field.
What is the gravitational potential energy formula?
GPE = mass x gravity x height J = kg x N/kg x m
What is kinetic energy?
Energy due to movement.
What is the formula for kinetic energy?
KE = 1/2 x mass x speed^2 J = 1/2 x kg x m/s^2
What do falling objects convert what into?
Potential energy into kinetic energy.
What is the formula for work done by brakes?
1/2 x m x v^2 = F x d
1/2 x kg x m/s^2 = N x m
Why do meteors and space shuttles entering the atmosphere burn up?
Friction with particles in the atmosphere.
What happens when work is done to an elastic object?
The energy is stored by the object as elastic potential energy.
What is the limit of proportionality?
The maximum force that an elastic object can take and still extend proportionally.
What is the formula for spring extension?
Force = spring constant x extension N = N/m x m
What is power?
The rate at which work is done.
What is the formula for power?
Power = Energy transferred / time J/s = J / s
What is one watt?
One joule of energy transferred per second.
What are two ways to measure power output?
- Timed run upstairs
2. Timed acceleration
What does the timed run upstairs measure?
The potential energy gained.
What does the timed acceleration measure?
The kinetic energy gained.
