BRAINCAKEMotion
Revision notes for Motion in Edexcel Physics (8PH0). 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.
- 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.