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Revision notes for Motion in Edexcel Physics (8PH0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Scalars and VectorsA scalar quantity is a quantity that has magnitude only.
- Speed and VelocitySpeed Speed is a scalar quantity. speed = distance ÷ time Derived quantities that are based on one quantity divided by time are rates of change with…
- Average and Instantaneous SpeedAverage speed = total distance ÷ total time taken instantaneous speed is the speed at a particular time and is the gradient of the tangent of a…
- AccelerationAcceleration = change of velocity ÷ time taken for the velocity to change Acceleration is the rate of change of velocity.
- Displacement -Time and Distance-Time GraphsDisplacement-time graph Displacement is a vector quantity so can be negative or positive in one dimension.
- Velocity-Time GraphsThe gradient of a velocity-time graph is the acceleration.
- Acceleration-Time GraphsThe values on an acceleration-time graph are the gradient of the velocity-time graph.
- Adding ForcesForces are vectors and we can use vector addition.
- The Parallelogram RuleThe resultant of two vectors is the diagonal of a parallelogram formed where the sides of the parallelogram are composed from the two vectors.
- Free-Body Force DiagramsA free-body force diagram is a representation of an object showing the forces acting on the object.
- The Moment of a ForceThe moment of a force is the force × the perpendicular distance of the line of action of the force from the pivot.
- Centre of GravityThe weight of an object is caused by the gravitational attraction between the Earth and each particle that makes up the object.
- Moments Question 1Question: a uniform metre rule is balanced on a pivot at its 50 cm mark.
- Moments Question 2Question: a uniform plank of length 4.0 m and weight 200 N rests horizontally on two supports, A at the left end and B at the right end.
- Newton's First Law of MotionΣF = 0 An object will continue to move at the same speed in the same direction (or if at rest will remain at rest) unless acted on by a resultant…
- Newton's Second Law of MotionΣF = ma F = force (N) m = mass (kg) a = acceleration (ms-2) The acceleration of an object is directly proportional to the resultant force acting on…
- Newton's Third Law of MotionWhen two objects interact, the forces they exert on each other are equal and opposite.
- Constant AccelerationWhen a constant force acts on an object the acceleration is constant, directly proportional to the force and in the direction of the force.
- Distance from Average SpeedThe average velocity during uniform acceleration is halfway from the initial velocity to the final velocity.
- Constant Acceleration FormulaeThe constant acceleration formulae are known as the suvat formulae. s= displacement u= initial velocity v = final velocity a = acceleration t = time…
- Practical: Measuring gThe acceleration due to gravity can be measured using the apparatus above.
- Constant Acceleration Question 1Question: a car accelerates uniformly from 5.0 m s-1 to 25 m s-1 over a distance of 100 m.
- Constant Acceleration Question 2Question: a car travelling at 30 m s-1 brakes with a constant deceleration of 6.0 m s-2 until it stops.
- Resolving VectorsResolving vectors means splitting a vector into two component vectors at right angles to each other.
- Resolving Vectors at an AngleResolving a vector means splitting a vector into two component vectors at right angles to each other.
- Projectile MotionWith a projectile, after the initial force which is used to set the object in motion, the only force of significance acting on the projectile is the…
- Vertical throwsWith a projectile, after the initial force which is used to set the object in motion, the only force of significance acting on the projectile is the…
- Horizontal ThrowsA cannonball is fired horizontally at 15ms-1 from a cliff that is 21m high.
- Throwing Upwards and ForwardsA ball is kicked at 30° to the horizontal at a speed of 15ms-1 from a point 21 m above the ground where it lands.
- Projectile - Question 1A ball is thrown upwards: The only motion is vertical.
- Projectile - Question 2A golf ball is struck from level ground at 25 ms-1 at 40° above the horizontal.
On the specification
- Topic 2: Mechanics