P2.1 - Motion

Question 1

State different ways to measure time (and cons)

Answer 1

\+ use a stopwatch 
\+ use a light gate 
cons? 
there is a reaction time that affects the accuracy and precision 
is expensive to buy

Question 2

What is the equation for calculating average speed?

Answer 2

total distance (m)
average speed (m/s) = ————————
                                                   total time (s)

Question 3

How many meters are there in one mile?

Answer 3

1609m

Question 4

What is the difference between a scalar and a vector measurement?

Answer 4

Vector has a magnitude (size) and direction -> represented as an arrow ie. force

Scalar has only magnitude (size) but no direction.
ie. time on a stopwatch (10s)

Question 5

What is displacement and is it a vector or scalar?

Answer 5

+ The distance from the place you travel

+ is a vector (has direction)

Question 6

What is speed?

Answer 6

+ a scalar quantity (has no direction)
+ is a measurement
ie. 15m/s

Question 7

What is velocity?

Answer 7

+ A vector quantity
+ has a direction as well as a magnitude
ie. 15m/s south
+ is in a certain direction

Question 8

What is the change in velocity per second called?

Answer 8

acceleration

Question 9

what is the equation for acceleration?

Answer 9

change in velocity (m/s)
acceleration (m/s^-2) = ——————————
time (s)

Question 10

What is the term when a vehicle slows down (acceleration)?

Answer 10

deceleration

Question 11

What does a (diagonal) straight line mean on a distance time graph?

Answer 11

the object’s speed is constant because the gradient doesn’t change

Question 12

What does a horizontal line mean on a distance time graph?

Answer 12

the object is not moving

Question 13

What does a steep line mean on a distance time graph?

Answer 13

The steeper the line, the faster the object is travelling

Question 14

How do you calculate speed from a distance time graph?

Answer 14

1) Draw a right-angled triangle underneath the line
2) Find the change in distance and the change in time
3) Use the equation of speed to find out the answer

Question 15

What is the difference between a distance-time graph and a displacement-time graph?

Answer 15

+ a distance-time graph is scalar

+ a displacement-time graph’s gradient has a velocity

Question 16

what is the equation for velocity?

Answer 16

change in displacement
velocity = ——————————
time

Question 17

What does the gradient on a graph tell you?

Answer 17

the rate of change with time

Question 18

what does the change of speed or velocity tell you?

Answer 18

acceleration

Question 19

if the initial velocity is higher than the final velocity, how is the acceleration shown?

Answer 19

as a minus number

ie. -0.35 m/s^2

Question 20

What is the equation of motion?

Answer 20

v^2 - u^2 = 2as

Question 21

What is the equation to calculate kinetic energy?

Answer 21

kinetic energy (J) = 0.5 x mass (kg) x speed (m/s))^2

Question 22

If a question says that an object is at rest, what is its initial velocity?

Answer 22

0 m/s^2 (since it is not moving)

bro said m/s^2 how did this girl pattern up to get a grade 9
- if she can do it anyone can

Question 23

Convert 30mph to m/s

Answer 23

1 mile = 1609m 
1hr = 60m
60m = 3600s 
          d              48 270
s = ——   =  ————
           t                3 600
= 13m/s

Question 24

How many seconds are there in an hour?

Answer 24

3600

Question 25

How do you represent a vector?

Answer 25

With an arrow (length shows magnitude)

Question 26

what is the unit of acceleration?

Answer 26

m/s^2

Question 27

how is an object moving if it has a negative velocity?

Answer 27

In the opposite direction

Question 28

How do you figure out the speed on a distance-time graph?

Answer 28

Look at the gradient (speed is equal to gradient)

Question 29

what does a horizontal line mean on a distance-time graph?

Answer 29

that the object is not moving

Question 30

how do you calculate speed on a distance time graph?

Answer 30

draw a right-angled triangle and divide the change in distance by change in time

Question 31

how is a distance time graph different from a displacement time Graph?

Answer 31

• A distance time graph only shows the total distance travelled
• on displacement time graph, the gradient can be negative

Question 32

what does the gradient represent on a displacement time graph?

Answer 32

the velocity of an object

Question 33

how do you calculate acceleration from a velocity-time graph?

Answer 33

change in velocity
————————
change in time

Question 34

how do you calculate distance travelled on a velocity time graph?

Answer 34

measure the area below the line

Question 35

what unit is velocity measured in?

Answer 35

m/s

Question 36

what unit is kinetic energy measured in?

Answer 36

Joules (J)

Question 37

What is human reaction time?

Answer 37

0.2s

Question 38

describe in detail how to measure your walking speed

Answer 38

• measure the distance you walked

- divide it by the time taken to walk that distance

Question 39

Why does kinetic energy quadruple when the speed is squared?

Answer 39

Because it is relative to double the speed of the object (so 2x2 =4)

Question 40

Is acceleration a vector or a scalar?

Answer 40

A vector, as it is the rate of change in VELOCITY not speed.

So if an object is at a constant speed, but changing direction, it is still accelerating

Question 41

If a body is moving and it starts to slow down, is it still accelerating?

Answer 41

Yes, as it has changed it’s speed

Question 42

state methods to measure distance:

Answer 42

metre ruler
tape measures
ultrasound? (bit far-fetched but ig it works)