Forces and motion

Cards (9)

braking distance
the distance travelled by a vehicle during the time it takes for its brakes to act.
conservation of momentum
in a closed system, the total momentum before an event is equal to the total momentum after the event.
Momentum is conserved in any collision or explosion, provided no external forces act on the objects that collide or
explode
directly proportiona
a graph will show this if the line of best fit is a straight line through the origin
elastic
a material is elastic if it is able to regain its shape after it has been squashed or stretched
extension
the increase in length of a spring (or a strip of material) from its original length
gravitational field strength, g
the force of gravity on an object of mass 1 kg (in newtons per kilogram, N/kg). It is also the acceleration of free fall.
Displacement is the shortest distance between start and finish locations.
What is the range of a typical reaction time for humans?
0.2 seconds to 0.9 seconds
What effect does a parachute have on the frictional force acting on the parachutist?
A parachute greatly increases a parachutist's surface area, so will increase the number of collisions with air particles, increasing the frictional force.