Forces And Energy T1b Flashcards
What is a system?
A system is just a fancy word for a single object (e.g. the air in a piston) or a group of objects (e.g. two colliding vehicle) that you’re interested in.
What is the efficiency of a transfer?
The efficiency of a transfer is the proportion of the total energy supplied
What happens when a system changes?
When a system changes, energy is transferred. It can be transferred into or away from the system.
What happens when a force moves an object through a distance?
Work is done on the object and energy is transferred.
What is the equation for wok done?
Work done (j)= Force (N) x distance moved in direction of the force (m)
What is the equation for efficiency?
Efficiency = useful energy transferred by a device / total energy supplied to device
What is power?
Rate of energy transfer.
What is the equation for power?
Power (W) = work done (J) / time taken (s)
What is a force?
A force is a push or a pull on an object that is caused by something interacting with it.
What is a free body force diagram?
A free body force diagram shows an isolated body (an object or system on its own), and all the forces acting on it.
What happens when an object is in equilibrium?
All of the forces acting on an object combine to give a resultant force of zero.
What is a moment?
The turning effect of a force.
What is the equation for a moment of a force?
Moment of a force (Nm) = force (N) x distance (m)
What is the sum of the clockwise moments?
The sum of the anticlockwise moments.
