Forces and Motion
Revision notes for Forces and Motion in OCR Physics A (H156). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Average SpeedThe average speed of an object is calculated from the total distance travelled and the total time taken.
- Displacement and VelocityBoth displacement and velocity are vector quantities.
- Displacement on a Velocity-time GraphThe displacement of an object is given by the area under its velocity-time graph.
- AccelerationAcceleration is the rate of change of velocity.
- Equations of Motion - Uniform AccelerationAcceleration is the rate of change of velocity.
- Free Fall Under GravityAll masses exert equal and opposite gravitational forces on each other.
- Projectile MotionA projectile is an object upon which the only force is gravity.
- Car Stopping DistancesThe stopping distance of a car is the distance travelled from when the driver first sees a reason to stop to when the vehicle stops. stopping…
- Weight, Mass, AccelerationThe mass of an object depends on how much matter it contains.
- Centre of MassAn object's gravitational force (its weight) acts through a point called its centre of gravity.
- Free-Body Force DiagramsA free-body force diagram isolates all the forces acting on an object.
- Drag and Terminal VelocityAn object moving through a fluid (e.g. air or water) experiences a resistive drag force from the fluid.
- Moments and EquilibriumAn object in equilibrium has no net force acting on it and no net moment (rotational equilibrium).
- Couples and TorquesA couple is a pair of forces that are parallel but act along different lines.
- Forces in EquilibriumIf an object on which forces are acting is held at rest then the resultant of these forces must be zero.
- Density and PressureThe density of a substance is its mass per unit volume.
- Pressure in Fluids and Archimedes PrincipleGases and Liquids (fluids) exert pressure on surfaces because of the constant collisions of their molecules with the surfaces.