Forces and Energy Flashcards
(20 cards)
When a system changes…
energy is transferred. Some energy is dissipated and stored in less useful ways.
How you define your system changes…
how you describe the energy transfers that take place.
What is a closed system?
One that’s defined so that the net change in energy is zero.
What are the 3 ways energy can be transferred?
By heating
By forces doing work
By Electrical equipment
If force moves an object…
Work is done.
What is the formula for work done?
E = F * d
One joule of work is done when…
a force of one newton causes an object to move a distance of one metre.
How to work out efficiency?
Useful energy transferred/total energy supplied to device.
What is power?
The rate of energy transfer.
What is the unit for power?
Watts (W) 1W = 1J/s
What is the formula for power?
P = E/t
What is a force?
A push or pull on an object that is caused by it interacting with something.
What do interacting magnetic fields cause?
Attraction or repulsion between magnetic objects.
The electrostatic force causing attraction and repulsion between electrical charges is due to…
interactions between their electric fields.
What should a free body diagram include?
Every force acting on the body.
What do the sizes and direction of the arrows show in a free body diagram?
The relative magnitude of the forces.
The directions of the forces.
Objects in equilibrium have a resultant force of…
0
Objects in equilibrium are either…
stationary or moving at a constant speed.
How can you deal with forces that act at awkward angles?
Can be split into two components at right angles to each other.
How can you split a force?
Draw it on a scale grid. Add horizontal and vertical components along grid lines. Measure them.
