What are the standard units of mass, distance, velocity, acceleration, force, time, gravitational field strength, moments, and momentum | Mass: kg, distance: m, velocity: m/s, acceleration: m/s², force: N, time: s, GFS: N/kg, moment: Nm, momentum: kg m/s |
Distance time graphs and average speed | Gradient = speed (distance/time), average speed = total distance/total time, acceleration curves graph |
Velocity time graphs and acceleration | Gradient = acceleration (velocity/time), area under graph = distance, horizontal line = constant velocity |
Speed equations | v²=u²+2as, a=(v-u)/t, s= |
Effects of forces | Changes in: speed, shape, and direction |
Types of forces | Gravitational, electrostatic, thrust, upthrust, air resistance, compression, tension, and reaction |
How do vector quantities differ from scalar? | Vector quantities have both direction *and* magnitude, while scalar quantities only have magnitude (e.g. velocity vs speed) |
Examples of vector quantities | Forces, velocity, acceleration, displacement, weight |
Examples of scalar quantities | Speed, energy, density, power, mass |
Resultant forces | One force to rule them all... cancel out vertical/horizontal forces until you see the overall direction and magnitude affecting the object |
Friction | Opposes motion |
Newton's second law | F=ma |
Weight, mass, gravitational field strength | W=mg |
Stopping distance | Thinking distance (dependent on intoxication, tiredness, distractions, speed) + braking distance (dependent on road conditions, brake pad conditions, weather, vehicle mass, speed) |
Falling objects' forces | Gravity vs air resistance, when equal the object is travelling at terminal velocity |
Hooke's law | Extension of an elastic object is directly proportional to the force applied, up to the limit of proportionality |
Elasticity | The ability of a material to recover its original shape after being deformed |
Momentum equation and conservation | p=mv, total momentum of all objects prior to collision = total momentum of all objects post collision, therefore mv=mv can be used to calculate masses or velocities in a system. |
Momentum and safety | Car safety features exist to slow the transfer of momentum, as a lower deceleration is less damaging than a rapid one. Seat belts have a bit of stretch so you still stop against the seat instead of the window, but you can go a little bit forward.“Speed has never killed anyone. Suddenly becoming stationary, that's what gets you.”
― Jeremy Clarkson |
Force, change in momentum, time taken | Force = change in momentum/time taken, F=(mv-mu)/t |
Newton's third law | Every action has an equal and opposite reaction |
Moment equation | Moment = force x perpendicular distance from pivot |
Where does weight act? | Centre of gravity |
How do you figure out the moments at either end of a beam with a mass somewhere along it? | Measure distances, use moment=Fd to calculate moments at both ends |