Forces and energy Flashcards
What is a system?
A single object or a group of objects
What is efficiency?
The proportion of total energy supplied that ends up in useful energy stores
How can energy be transferred?
+Heating +Forces doing work +Electrical equipment
What happens if a force moves?
+Work is done
What is the equation for work done?
+Work done = force x distance
What is power?
+Power is the rate of energy transfer
+Unit of power is watt (W)
+1 W = 1J/s
What is a force?
+A push or pull on an object that is caused by interacting with something.
+It is a vector (has both size and direction)
+Whenever two objects interact, both objects feel an equal and opposite force (N’s3rd law)
What is a free body force diagram?
+Shows an isolated body (an object or system of its own) and all forces acting on it.
What is the resultant force?
+The overall force on a point or an object.
+Can sometimes be called the net force
What is an object in equilibrium?
When all forces of an object combine to give a resultant force of zero.
What is a moment?
The turning effect of a force.
What is a pivot?
The centre of rotation
What is the equation for a moment?
What are gears?
- Wheels with teeth around their rims.
- Can be used to transfer rotational forces.
How aret the ratio of speeds and the ratio of gears linked?
They are inversely proportional.
What is the equation for power?
How do you work out the vertical side of a diagonal force?
v x sin(Ø)
How do you work out the horizontal side of a diagonal force?
V x cos(Ø)
How would you find the component of weight parallel to the incline?
- W x sin(Ø)
- =mg x sin(Ø)
- Measured in Newtons
How would you find the component of weight perpendicular to the incline?
- W x cos(Ø)
- =mg x cos(Ø)
- Measured in Newtons
What is the general rule that allows us to compare the moments and radii of gears?
Ratio of gears’ radii = Ratio of moments = Ratio of teeth
How do you get the maxium turning effect?
Push at right angles
