physics 2a- motion, energy and electricity Flashcards
what force attracts all masses?
gravity
what is gravitational force?
the force of attraction between all masses
what is mass?
the amount of stuff in an object
what is weight caused by?
the pull of the gravitational force
which one changes? mass or weight
weight
what is weight measured in?
newtons (n)
what is a resultant force?
an overall force on an object
what does the overall effect of the force do?
decides the motion of the object (whether it accelerates, decelerates or stays at steady speed)
how is the overall effect found?
by adding or subtracting them
which direction does gravity act upon?
downwards
resultant force is a change in…
velocity
what does friction do?
slows things down
what does air resistance do?
causes things to fall at different speeds
what does the frictional force depend on?
shape and area
what is a safe speed to hit the ground?
15mph
what is stopping distance?
thinking distance+braking distance
what is thinking distance?
the distance the vehicle travels during the drivers reaction time
what is braking distance?
the distant the car travels under the braking force
two main factors that affect thinking distance:
how fast you’re going
how dopey you are
four main factors that affect braking distance:
how fast you’re going
how good your brakes are
how good the tyres are
how good the grip is
