From Motion to Forces
Part of the Mechanics section of Coddy's Physics journey. Lesson 39 of 94.
Measure the motion, get the acceleration, and the second law gives the net force. Subtract the forces you know:
a = Δv / Δt, ΣF = m a
An elevator that speeds up on its way up: the cable pulls harder than the weight.
Speeding up on the way up: the cable pulls harder than the weight.
A scale shows the normal force N: your apparent weight.
Challenge
A 1500 kg car speeds up from rest to 24 m/s in 8 s, while air and road resistance hold it back with 500 N. Find the driving force F.
Try it yourself
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Mechanics
1Vectors and Newton's Laws
Right TrianglesWhat is a Vector?Adding VectorsAxes and DirectionsVector ComponentsForces Around UsFriction and TensionNewton's First LawNewton's Second LawNewton's Third LawRecap - Net Force2Friction
What is Friction?Static FrictionKinetic FrictionFriction and Newton's LawsRecap - Sliding Crate3Inclined Planes
Forces on an InclineGravity ComponentsFrictionless InclineIncline with FrictionWill It Slide?Recap - Ramp Challenge6Projectile Motion
Independent AxesHorizontal LaunchLaunch at an AngleRange and Max HeightRecap - Hit the Target9Work and Energy
WorkKinetic EnergyWork-Energy TheoremGravitational PEConservation of EnergyPowerRecap - Roller Coaster12Impulse and Momentum
MomentumImpulseConservation of MomentumElastic CollisionsInelastic CollisionsRecap - Air Track15Simple Harmonic Motion
What is SHM?Mass on a SpringThe PendulumSHM GraphsEnergy in SHMRecap - Oscillator