describe examples of the forces acting on an isolated solid object or system

describe, using free body diagrams, examples where several forces lead to a resultant force on an object and the special case of balanced forces (equilibrium) when the resultant force is zero
qualitative only

use scale drawings of vector diagrams to illustrate the addition of two or more forces, in situations when there is a net force, or equilibrium

Limited to parallel and perpendicular vectors only

recall and apply the equation for momentum and describe examples of the conservation of momentum in collisions:

momentum (kg m/s) = mass (kg) × velocity (m/s)

select and apply Newton’s second law in calculations relating force, change in momentum and time:

change in momentum (kg m/s) = resultant force (N) × time for which it acts (s)

apply Newton’s first law to explain the motion of objects moving with uniform velocity and also the motion of objects where the speed and/or direction changes

explain with examples that motion in a circular orbit involves constant speed but changing velocity

qualitative only

describe examples in which forces cause rotation

define and calculate the moment of examples of rotational forces using the equation:

moment of a force (N m) = force (N) × distance (m) (normal to direction of the force)

explain, with examples, how levers and gears transmit the rotational effects of forces

explain that inertial mass is a measure of how difficult it is to change the velocity of an object and that it is defined as the ratio of force over acceleration

recall and apply Newton’s second law relating force, mass and acceleration:

force (N) = mass (kg) × acceleration (m/s²)

use and apply equations relating force, mass, velocity, acceleration, and momentum to explain relationships between the quantities

explain methods of measuring human reaction times and recall typical results

explain the factors which affect the distance required for road transport vehicles to come to rest in emergencies and the implications for safety

explain the dangers caused by large decelerations and estimate the forces involved in typical situations on a public road

given suitable data, estimate the distance required for road vehicles to stop in an emergency, and describe how the distance varies over a range of typical speeds

in the context of everyday road transport, use estimates of speeds, times and masses to calculate the accelerations and forces involved in events where large accelerations occur