Motion Graphs and Forces Flashcards
what does the gradient represent on a distance/time graph?
the gradient is equal to the speed of the object (velocity)
what is the equation for speed?
distance ÷ time
what is the equation for the average speed?
total distance ÷ total time
what does the gradient of a velocity/time graph represent?
the gradient is equal to the acceleration of the object
how do you work out the distance travelled on a velocity/time graph?
look at the area under the gradient
e.g. if it makes a triangle under the line you then do 1/2 x base x height to work out the distance
what is the units for velocity?
m/s
what is the units for acceleration?
m/s2
if a ticker tape timer produces dots at a frequency of 50Hz, how many dots are produced per second?
50
on a ticker tape timer, how can you tell if the dots are moving at a constant speed?
the dots are equally spready apart
on a ticker tape timer, how can you tell if the dots accelerating?
the dots will get further apart
on a ticker tape timer, how can you tell if the dots decelerating?
the dots will get closer together
what is aceleration?
the rate of change of velocity
rate of change = 1/t
what is the equation for acceleration?
a = v - u ÷ t ( v = final velocity, u = initital velocity)
change in velocity ÷ time taken
a = Δv ÷ t = m/s x 1/s = m/s2
how do velocity and acceleration act in decelration?
in opposite directions causing the velocity to get smaller
what is a scaler quantity?
quantities that have magnitudes or a size only
what is a vector quantity?
quantities that have magnitude and direction
give some examples of scalars
mass
temprature
distance
time
speed
energy
give some examples of vectors
velocity
force
weight
what is Newton’s first law?
objects will remain at rest or continue to move at a constant speed unless acted upon by a resultant force
if F=0 a =0m/s2
(F = resultant force)
what is Newtons second law?
resultant force is directly proportional to the rate of change of momentum
F∝ mv - mu ÷ t
(F = resultant force, ∝ = directly proportional, t = rate of change, mv - mu = momentum)
F = mv-mu ÷ t
F = m (v-u) ÷ t [acceleration]
F= ma
resultant force = mass x acceleration
what are the units used in the equation for Newton’s second law?
resultant force = mass x acceleration
F = ma
F = resultant force (N)
m = mass (kg)
a = acceleration (m/s2)
what is static friction?
the friction acting on stationairy objects
what is dynamic friction?
the friction acting on moving objects
what is the control variable?
something that is constant and unchanged
what is thinking distance?
the distance a vehicle travels while the driver is reacting
what is breaking distance?
the distance a vehicle travels while the brakes are being applied until it stops
what is stopping distance?
thinking distance + breaking distance
give some factors that affect thinking distance
use of alcohol
use of drugs (il/legal)
distracted by passengers in the vehicle
tired
using a mobile
speed of car
give some factors that affect braking distance
mass of car
weather
tread of tyres
wornout breakes
level of grip on road
speed of car
if the distance = 8,000m and the time = 3,600s, calculate the average speed
average speed = total distance ÷ total time
= 8000 ÷ 3600
=2.2 m/s
describe the motion of a on this distance/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/866/907/q_image_thumb.jpg?1659507807)
a is stationairy because the gradient is a straight, vertical line
we did not move it we just let the device play
describe the motion of e on this distance/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/082/q_image_thumb.jpg?1659507808)
e is accelerating away from the origin
there is no constant speed
we started the pencil case at the device (origin) and then accelerated it away
describe the motion of b and c on this distance/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/088/q_image_thumb.jpg?1659507808)
b is moving fast at a constant speed
c is moving fast at a consant speed but faster than b, almost double
to achieve this graph we flipped the sensor from its side to face upwards and we moved a pencil case upwards and away from it in a constant motion
describe the motion of f on this distance/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/106/q_image_thumb.jpg?1659507808)
f is movimg at a fast away from the device (origin) and constant pace but then remains stationairy at a point
describe the motion of a on this velocty/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/521/q_image_thumb.jpg?1659507808)
a is moving at a constant speed
describe the motion of d on this velocity/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/858/q_image_thumb.jpg?1659507809)
d is deccelerating at a constant rate
describe the motion of b and c on this velocity/time graph
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/872/q_image_thumb.jpg?1659507809)
b is acelerating at a constant rate
c is acelerating at a constant rate faster than b
in equilibrium or when stationionairy or moving a constant speed, what is the resultant force?
0N
calculate the resultant force and the accelertaion of this 5.0kg mass
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/889/q_image_thumb.jpg?1659507810)
F = 1050-895
= 155N (downwards)
as F = ma
a = F ÷ m
= 155÷5
= 31 m/s2
calculate the resultant force and the accelertaion of this 5.0kg mass
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/867/959/q_image_thumb.jpg?1659507810)
F = 100 + (-80)
= 20N (to the left)
as F = ma
a = F ÷ m
= 20 ÷ 5
= 4 m/s2 (to the left)
calculate the resultant force and the accelertaion of this 5.0kg mass
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/868/036/q_image_thumb.jpg?1659507810)
F = 10 + (-15)
= 5N (downwards)
as F = ma
a = F ÷ m
= 5 ÷ 5
=1 m/s2
calculate the resultant force and the accelertaion of this 5.0kg mass
![](https://s3.amazonaws.com/brainscape-prod/system/cm/131/868/082/q_image_thumb.jpg?1659507811)
F = 100 + (-500)
= 400N (downwards)
as F = ma
a = F ÷ m
= 400 ÷ 5
=80m/s2 (downwards)