SP1- Motion

Question 1

What is weight

Answer 1

A force that acts towards the centre of the earth

Question 2

What do all forces have

Answer 2

Magnitude (size) and a direction

Question 3

What are forces measured in

Answer 3

Newtons (N)

Question 4

What are vector quantities

Answer 4

Quantities that have both size and direction

So forces are vectors

Question 5

How are forces shown in diagrams

Answer 5

Using arrows - longer arrows represent larger forces

Question 6

What does the weight of a person depend on

Answer 6

The mass

Question 7

What does mass measure

Answer 7

The amount of matter in something and does not have a direction

Question 8

What is a scalar quantity

Answer 8

Quantities that do not have a direction

Examples include distance, speed, energy and time

Question 9

What is displacement

Answer 9

The distance covered in a straight line and has a direction

Displacement is usually less than distance travelled because of bends and Turks in a journey

Question 10

What does the speed of an object tell you

Answer 10

How far it moves in a certain time

Question 11

What is velocity

Answer 11

Is speed in a particular direction eg a car may have s velocity of 20m/s northwards

Question 12

Tell me some examples of vector quantities

Answer 12

Acceleration - a measure of how fast velocity is changing

Momentum - a combination of mass and velocity

Question 13

What are the common units for speed

Answer 13

M/s or km/h and mph

Question 14

Tell me the speed distance time triangle

Answer 14

X on top or D (distance) and S (speed) X T(time) on the bottom

Question 15

What’s the average speed

Answer 15

Worked out from the total distance travelled and time taken

Question 16

What’s the instantaneous speed

Answer 16

Is the speed at a particular point in a journey

Question 17

How can you measure speed in a lab

Answer 17

You need to measure a distance and a time, for fast moving objects - use light gates to measure time and will be more
Accurate than a stopwatch

Question 18

How can a journey be represented

Answer 18

On a distance/time graph

Question 19

What does a distance/time graph tell us about speed

Answer 19

Horizontal lines means the object is stationary

Straight, sloping lines mean the object is travelling at constant speed

The steeper the line the faster the object is travelling

Have sled is calculated from the GRADIENT Of the line

Question 20

How do you work out the gradient

Answer 20

The vertical difference between two points on s graph divided by the horizontal difference between the same two points

Then working out the gradient shows the speed

Question 21

What is a change in velocity

Answer 21

Acceleration - it’s a vector

If a moving object changes its velocity or direction it is accelerating

Question 22

What is the units of acceleration

Answer 22

M/s^2

So an acceleration of 10m/s^2 means that each second the velocity increases by 10m/s

Question 23

How do you calculate acceleration

Answer 23

Change in velocity (m/s) divided by time taken in seconds

The triangle is v-u on top and a X t on bottom

V is final velocity
U is the initial velocity
T is the time taken for change in velocity
A is acceleration

Question 24

What can acceleration mean

Answer 24

Doesn’t always mean getting faster - can also cause an object to get slower - sometimes called a deceleration and acceleration will have a negative value

Question 25

Tell me the equation to link initial velocity, final velocity and distance travelled

Answer 25

V^2 - U^2 = 2 X a X x

V is final velocity
U is Initial velocity
A is acceleration
X is distance

Question 26

What does the symbol g means

Answer 26

Gravity

It’s 9.8m/s^2 on earth but rounded to 10 in calculations

Question 27

How can the changing velocity be shown

Answer 27

By a velocity/time graph

Question 28

Tell me about velocity/time graphs

Answer 28

A horizontal line means the object is travelling at constant velocity

A sloping line shows that the object is accelerating, the steeper the line - the greater the acceleration

If the line slopes down to the right -
The object is decelerating

You can find the acceleration of an object from the gradient of the line on a velocity/time graph

A negative velocity (line below horizontal axis) shows the object is moving in the opposite direction

Question 29

How can you calculate the distance travelled from a graph

Answer 29

Multiplying velocity and a time - split the shape into triangles and/ or rectangles and find there areas separately and add them together