forces and movement Flashcards
what’s the relationship between acceleration and force
if you double the force you double the acceleration
what does a graph of acceleration against force look like
a straight line through the origin
what does a graph of acceleration against force show
acceleration is directly proportional to force
what is the relationship between acceleration and mass
if you double the mass you half the acceleration
what does a graph of acceleration against 1/mass look like
straight line through the origin
what does a graph of acceleration against 1/mass show
acceleration is inversely proportional to mass
what is the equation for acceleration
acceleration = force/mass
what is the equation for acceleration in symbols
a = F/m
what is thinking distance
the distance travelled while the driver reacts
what is the relationship between speed and thinking distance
thinking distance = speed x reaction time
what is breaking distance
the distance travelled while breaking until the car comes to a stop
4 factors affecting thinking distance
- tiredness
- under the influence of drugs/alcohol
- distractions e.g phone
- eyesight
4 factors affecting breaking distance
- conditions of the roads
- conditions of the breaks
- conditions of the tyres
- mass of vehicle
how do you find the deceleration of the braking from velocity-time graph
find the gradient of the slope
how do you find thinking distance and breaking distance on a velocity-time graph
area under the line
how do you calculate total stopping distance
thinking distance + breaking distance
when an object falls what is the one initial force acting on it
weight
once an object starts to fall faster what is the force that acts in the opposite direction to weight
air resistance
what does air resistance do to a falling object
makes it accelerate less/reduce acceleration
what happens when air resistance gets so large t equals weight
there is no net force and the object stops accelerating. it reaches terminal velocity
what is the definition for terminal velocity
the maximum speed a falling object can reach
how does a parachute effect ai resistance
- when a parachute opens there is an immediate increase in surface area
- therefore and immediate increase in air resistance
what happens after the parachute has been open for a while
- the decrease in speed reduces the air resistance until a new, slower terminal velocity occurs
