p9-motion Flashcards
what is the equation for speed
speed=distance/time
what does the gradient of the line on a distance time graph represent
speed
what does a horizontal line mean on a distance time graph
the object is stationary so speed is 0
what does the line look like on a distance time graph when the object is travelling at a constant speed
a straight line that slopes upwards
what does velocity mean
speed in a given direction
if a car is travelling round a roundabout at a constant speed is there constant velocity
no
what does displacement mean
distance travelled in a given direction
what is the equation for acceleration
acceleration(a)=change in velocity(V-U)(final velocity - initial velocity) / time(s)
what is a vector quantity
something that has magnitude(size) as well as direction
what is a scalar quantity
something that only has magnitude(size)
is speed a scalar or vector quantity
scalar because it only has magnitude
is velocity and displacement a scalar of vector quantity
vector because it has magnitude as well as direction
what is the unit of acceleration
m/s squared
what does deceleration mean
when an object slows down
what can a motion sensor that is linked to a computer do
record how the velocity of an object changes
what does a straight line going up on a velocity time graph mean
the increase in velocity was the same every second, meaning that the acceleration is constant.
what does a line going up show
the object is accelerating
what does the gradient of the line of a velocity time graph give you
acceleration
what does a straight line on a velocity time graph show
the velocity is constant
what is the acceleration when there is a flat line an a velocity time graph
0 as the gradient is 0
what happens when brakes are applied to a vehicle
it decelerates as the acceleration is negative
what does the area under a flat line on a velocity time graph mean
distance
how do you work out how far something has travelled while decelerating
the area of the triangle under the line
what units must be used for speed or velocity before putting them on a graph or using them in an equation
m/s
what does the line look like on a distance time graph for an object moving at a constant speed
straight line sloping upwards
what does the gradient of the line on a distance time graph represent
speed
how do you work out the gradient
height of triangle/base of triangle
what does a curved line on a distance time graph mean
the speed is changing
what is a tangent
a straight line that touches a point on the curve without cutting through the curve
what does the gradient of the tangent tell you
the speed of the object at the moment the tangent touches the curve on the graph
what is the formula average velocity
1/2 (u+v)
what does v squared - u squared = 2as mean
final velocity squared - initial velocity squared = 2 x acceleration x distance
