Forces

Question 1

How do you measure the time of a falling object?

Answer 1

Light gates

Question 2

What affects the precision and accuracy of time measurements?

Answer 2

Reaction time

Question 3

How does a light gate work?

Answer 3

A timer starts and stops when an object interrupts a light beam

Question 4

What is an advantage of using a light gate?

Answer 4

You can measure very short periods of time

Question 5

Give a way of measuring distance accurately

Answer 5

Ultrasound

Question 6

What does ultrasound use?

Answer 6

High-frequency sound waves

Question 7

How does ultrasound work?

Answer 7

The device measures the time taken for a pulse to travel there and back. It uses this value and the speed of the pulse to measure the distance.

Question 8

The equation for uniform motion speed

Answer 8

Average speed (m/s) = total distance (m) // total time (s)

Question 9

What is non-uniform motion

Answer 9

Motion where speed changes

Question 10

SI units

Answer 10

Metre and seconds

Question 11

Metres in a mile

Answer 11

1609m

Question 12

How do you convert between units?

Answer 12

With the speed equation

Question 13

What is the difference between a vector and a scalar?

Answer 13

Vectors have magnitude and direction, scalars only have a magnitude

Question 14

An example of a vector

Answer 14

Force, where the length of the arrow shows the magnitude (size)and the direction shows the direction

Question 15

An example of a scalar

Answer 15

Measurement made with a stopwatch e.g. magnitude 10s

Question 16

Difference between displacement and distance

Answer 16

Distance is total distance travelled while displacement is the distance from the starting point

Question 17

What is the difference between speed and velocity?

Answer 17

Speed is scalar, velocity is vector

Question 18

Explain positive and negative velocity

Answer 18

A car traveling to the west has a velocity of -40mph while a car travelling to the east has a velocity of +40mph

Question 19

What is acceleration?

Answer 19

Change in velocity per second

Question 20

How do you accelerate?

Answer 20

You go from one speed to another

Question 21

Uniform acceleration

Answer 21

Acceleration does not change

Question 22

Formula for acceleration

Answer 22

Acceleration (m/s2) = change in velocity (m/s) // time (s)

Question 23

Units for acceleration

Answer 23

m/s2

Question 24

What does a graph of distance against time mean?

Answer 24

• A diagonal straight line means moving at constant speed because the gradient does not change
• A horizontal line means the object is not moving
• The steeper the line the faster the speed

Question 25

How is a distance-time graph different from a displacement-time graph?

Answer 25

Distance-time shows total distance travelled.
In a displacement-time graph, the gradient can be positive, negative or zero.
The gradient of the displacement-time graph is velocity.

Question 26

Time against x-axis

Answer 26

Rate of change with time

Question 27

Gradient of a velocity-time graph

Answer 27

Vector acceleration

Question 28

Area under a speed-time graph

Answer 28

Distance

Question 29

Area under velocity-time graph

Answer 29

Displacement

Question 30

What is the equation of motion used for?

Answer 30

For objects with a constant acceleration

Question 31

Equation of motion

Answer 31

(Final velocity (m/s))2 - (initial velocity m/s))2 = 2 x acceleration (m/s2) x distance (m)