Motion

Question 1

What are important things to remember about a distance-time graph

Answer 1

1. Gradient=speed
2. Flat sections = stationary
3. Straight uphill/ downhill= steady speed
4. Steeper the graph= faster it’s going
5. Downhill= going towards starting point
6. Curves= acceleration/deceleration
7. Steepening curve= speeding up
8. levelling off curve= slowing down

Question 2

why is the gradient of a distance-time graph the speed

Answer 2

speed= distance divided by time

so gradient tells you how fast an object is going because the gradient is the change in distance (vertical axis) divided by the change in time (horizontal axis)

Question 3

How do you calculate speed from a distance-time graph

Answer 3

horizontal axis

so the gradient, always have speed in m/s

Question 4

what is acceleration

Answer 4

1. how quickly velocity is changing

this change can be in speed or direction or both

Question 5

what’s the formula for acceleration and what are the units for acceleration

Answer 5

(v-u) change in v
—– or acceleration=————-
a x t time taken

UNITS AR M/S^2!!!!!!!!!!!

Question 6

what are important things to remember about a velocity-time graph

Answer 6

1. gradient= acceleration
2. flat sections= steady speed
3. steeper the graph= greater acceleration or deceleration
4. uphill= acceleration
5. downhill= deceleration
6. area under any section of the graph= distance travelled in that time interval
7. curve= changing acceleration

Question 7

What is the difference between speed and velocity

Answer 7

Speed is just how fast you’re going (eg 20m/s) but has no regard to the direction.

Velocity is how fast you are going with the direction specified

Question 8

how to calculate acceleration from a velocity-time graph

Answer 8

acceleration =gradient

horizontal axis

Question 9

how to calculate the velocity from a velocity-time graph

Answer 9

read the value off the velocity axis

Question 10

how to calculate the distance travelled from a velocity-time graph

Answer 10

distance in any time interval= area under the graph

so change on the x axis times the change on the y axis

Question 11

what does friction do

Answer 11

slows things down

1. if an object has no force propelling it, it will always slow down and stop due to friction
2. friction always happens in opposite direction to movement
3. to travel at a steady speed the driving force need to balance the frictional forces
4. friction occurs between two surfaces in contact or when an object passes through a fluid (drag)