P9 Flashcards
Motion
What does the gradient of a distance-time graph represent ?
speed
Give the equation for constant speed
distance travelled (m)/time (s) = speed (m/s)
How would a stationary object be represented on a distance-time graph ?
straight horizontal line
What is velocity ?
speed in a given direction
Is the velocity of a car doing doughnuts at a constant speed constant ?
no because direction constantly changing, so velocity thus is also constantly changing
What is acceleration ?
the change in VELOCITY per second (m/s^2)
- technically includes deceleration also (just a negative version)
Give the equation for acceleration
(v - u)/t = a
t = time in seconds
u = initial velocity
v = final velocity
a = acceleration
Describe the method for an investigation into acceleration based on the steepness of a ramp using a laptop
- place motion sensor linked to an interface linked to a laptop at the top of an inclined plane
- attach a piece of card to a trolley so that it stands on end at its back
- hold the trolley with the card against the motion sensor at the top of the inclined plane and start the programme at the same time as releasing the trolley
- stop the programme when it reaches the end of the ramp
- laptop displays a velocity-time graph accordingly
- repeat but with a steeper ramp
- the gradient of the straight line on the graph (representing acceleration) should be steeper than before
What does the gradient on a velocity-time graph represent ?
acceleration
What does the area under a velocity-time graph represent ?
total distance travelled in a given direction (displacement)
Describe how to find the velocity at a certain point on a distance-time graph where the velocity is not constant (graph is curved)
- draw upwards from the given point on the x-axis until meeting the line
- draw a tangent where they meet
- work out the gradient normally
