Forces + Energy Flashcards
Name four contact forces
Friction, upthrust, air/water resistance (drag), reaction force
Name three non-contact forces
Gravity, magnetism, electrostatic
How can you identify balanced forces
Forces of equal magnitude acting in opposite directions on the same object OR Forces acting on an object producing a resultant force of zero Newtons
Define weight
The force due to gravity pulling on an object’s mass
What is the name of the single force which represents the combined effect of all the forces acting on an object
Resultant force
If two forces acting on an object in opposite directions are the same size, what would happen to that object
Either not move, or move at constant speed
If two forces acting on an object in opposite directions are not the same size, what would happen to that object
It would change speed: accelerating/ speed up or decelerate/ slow down
Which force resists movement when two materials are in contract
Friction
What is the name of the support force from a solid object
Reaction force
Which piece of equipment do you measure forces with
Newtonmeter
What is a gravitational field strength
The strength of gravity at the surface of a plant, which is determined by the planets mass
What is the gravitational field strength on the surface of the earth
10 N/kg or more accurate 9.8 N/kg
What is the formula which links gravitational field strength, mass and weight
Weight = mass x gravitational field strength
What unit is weight measured in
Newtons
What unit is mass measured in
Kg
Does an objects mass stay the same, or vary, on different planets
Stays the same
Does an objects weight stay the same, or vary, on different planets
Varies
What is another phrase we can describe the ‘energy transferred’ in a process
Work done
What units do we use to measure ‘energy transferred’ or ‘work done’
Joules
What is the formula which links distance moved, force and work done
Work done = force x distance moved
What are the nine main energy stores
Gravitational, elastic, thermal, nuclear, chemical, kinetic, vibrational, electrostatic, magnetic
What is power a measure of
The rate of energy transfer
What unit is is used to measure power
Watts
What is the formula linking energy transferred, power and time taken
Power = energy transferred / time taken
What do we call wasted energy
Dissipated energy
What is the name given to the turning effect of a force
The moment
What is the formula linking force, moment and perpendicular distance from pivot
Moment = force x perpendicular distance from pivot
What unit is used to measure moments
Newton metre (Nm)
Moments are in equilibrium (or balanced) in what situation
Clockwise moment = anti-clockwise moment
