P5 (part 2)

Question 1

What is meant by ‘distance’?

Answer 1

how far an object has moved/travel

Question 2

Distance is a scalar quantity – what does this mean?

Answer 2

it only has a magnitude (size) but doesn’t have a direction

Question 3

What is meant by ‘displacement’?

Answer 3

is the distance and direction an object moves in a straight line between the start and finish

Question 4

Displacement is a vector quantity – what does this mean?

Answer 4

it has a magnitude and a direction

Question 5

Why is the speed of a journey rarely constant?

Answer 5

when your unable to maintain the constant speed with factors affecting that

Question 6

What factors could the average speed of a journey depend on?

Answer 6

• weather
• distance
• surface your travelling on
• age
• traffic lights
• fitness

Question 7

What do you think the average speeds are for : walking, running, cycling, car, sound?

Answer 7

〜 mean ‘average’

Walking 〜1.5 m/s
Cycling 〜6 m/s
Running 〜3 m/s
Sound 〜330 m/s

Question 8

What measurements would you need to take to determine the speed of an object?

Answer 8

we need to mention: time + distance

• the equipment suitable for distance would be a : trundle wheel (more accurate than a tape measurer)
• the equipment suitable for time would be a : stopwatch

Question 9

What is the equation for calculating speed?

Answer 9

distance (m) = speed (m/s) x time (s)

s = v x t

Question 10

What is the difference between speed and velocity?

Answer 10

• speed is a scalar quantity, so it has a magnitude only

- velocity is a vector quantity so it has a magnitude AND a direction

Question 11

What is the definition velocity?

Answer 11

The speed of an object in a given direction

Question 12

Why does an object moving in a circle at a constant speed, NOT have a constant velocity?

Answer 12

• although the speed is constant, the direction is NOT

- this means the velocity is constantly changing

Question 13

On a distance -time graph there’s different points, what are there and what does it show?

Answer 13

• a curved line upwards shows acceleration
• a sloped gradient shows constant speed
• a steeper gradient show a faster constant speed
• a horizontal line shows it’s stopped
• a sloped gradient shows constant speed back towards start
• a curved downwards shows deacceleration

Question 14

Describe how to find the speed of the object at a particular time

ON A GRAPH

Answer 14

1: Draw a TANGENT to the curve at the moment in which you are interested
2: Calculate the GRADIENT of the TANGENT - this is the instantaneous speed.

Question 15

What is happening when an object is accelerating?

Answer 15

it speeding up

OR it’s slowing down at a negative acceleration

Question 16

What is the equation to determine the acceleration of an object?

Answer 16

acceleration (m/s2) = change in velocity (m/s) ÷ time (s)

a = Δv ÷ t

Question 17

On a velocity - time graph there’s different points, what are there and what does it show?

Answer 17

• in the beginning it will speed up in a positive direction (making it a positive acceleration)
• then will speed up more in the positive direction (making it a positive acceleration)
• when there’s a horizontal line there’s a constant speed in a positive direction
• then it slows down in a positive direction
• once again there’s a horizontal line where there’s a constant speed in a direction on (stopping) 0
• then it accelerates in a negative direction
• eventually there’s a constant speed in a negative direction