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level: Level 1 of Forces and Motion

Questions and Answers List

level questions: Level 1 of Forces and Motion

QuestionAnswer
What are the standard units of mass, distance, velocity, acceleration, force, time, gravitational field strength, moments, and momentumMass: 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 speedGradient = speed (distance/time), average speed = total distance/total time, acceleration curves graph
Velocity time graphs and accelerationGradient = acceleration (velocity/time), area under graph = distance, horizontal line = constant velocity
Speed equationsv²=u²+2as, a=(v-u)/t, s=
Effects of forcesChanges in: speed, shape, and direction
Types of forcesGravitational, 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 quantitiesForces, velocity, acceleration, displacement, weight
Examples of scalar quantitiesSpeed, energy, density, power, mass
Resultant forcesOne force to rule them all... cancel out vertical/horizontal forces until you see the overall direction and magnitude affecting the object
FrictionOpposes motion
Newton's second lawF=ma
Weight, mass, gravitational field strengthW=mg
Stopping distanceThinking distance (dependent on intoxication, tiredness, distractions, speed) + braking distance (dependent on road conditions, brake pad conditions, weather, vehicle mass, speed)
Falling objects' forcesGravity vs air resistance, when equal the object is travelling at terminal velocity
Hooke's lawExtension of an elastic object is directly proportional to the force applied, up to the limit of proportionality
ElasticityThe ability of a material to recover its original shape after being deformed
Momentum equation and conservationp=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 safetyCar 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 takenForce = change in momentum/time taken, F=(mv-mu)/t
Newton's third lawEvery action has an equal and opposite reaction
Moment equationMoment = 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