Retrieval Questions

Question 1

When is a measurement valid

Answer 1

When it measures what it is supposed to be measuring

Question 2

When is a result accurate

Answer 2

When it is close to the true value

Question 3

What are precise results

Answer 3

When repeat measurements are consistent with each other

Question 4

What is repeatability

Answer 4

How precise repeated measurements are when they are taken by the same person using the same equipment under the same conditions

Question 5

What is reproducibility

Answer 5

How precise repeated measurements are when they are taken by different people using different equipment

Question 6

What is the uncertainty of a measurement

Answer 6

The interval within which the true value is expected to lie

Question 7

Define measurement error

Answer 7

The difference between a measured value and the true value

Question 8

What type of error is caused by results varying around the true value in an unpredictable way

Answer 8

Random error

Question 9

What is a systematic error?

Answer 9

a consistent difference between the measured values and true values

Question 10

What does zero error mean?

Answer 10

a measuring instrument gives a false reading when the true value should be zero

Question 11

Which variable is changed or selected by the investigator?

Answer 11

independent variable

Question 12

What is a dependent variable

Answer 12

A variable that is measured every time the independent variable is changed

Question 13

Define a fair test

Answer 13

a test in which only the independent variable is allowed to affect the
dependent variable

Question 14

What are control variables?

Answer 14

variables that should be kept constant to avoid them affecting the dependent variable

Question 15

What is a physical quantity?

Answer 15

a property of an object or of a phenomenon that can be measured

Question 16

What are the S.l. units of mass, length, and time?

Answer 16

kilogram (kg), metre (m), second (s)

Question 17

What base quantities do the S.l. units A. K, and mol represent?

Answer 17

current, temperature, amount of substance

Question 18

List the prefixes, their symbols and their multiplication factors from pico to tera (in order of increasing magnitude)

Answer 18

Write it out

Question 19

What is a scalar quantity?

Answer 19

a quantity that has magnitude (size) but no direction

Question 20

What is a vector quantity?

Answer 20

a quantity that has magnitude (size) and direction

Question 21

What are the equations to resolve a force, F, into two perpendicular components, Fx and Fy?

Answer 21

Fx =Fcos0
Fy = F sin0

Question 22

What is the difference between distance and displacement?

Answer 22

distance is a scalar quantity
displacement is a vector quantity

Question 23

What does the Greek capital letter 🔺 (delta) mean?

Answer 23

Change in

Question 24

What is the equation for average speed in algebraic form?

Answer 24

V =🔺x /🔺t ( change in x over change in t)

Question 25

What is instantaneous speed?

Answer 25

the speed of an object over a very short period of time

Question 26

How can you calculate acceleration from a velocity-time graph?

Answer 26

acceleration is the gradient displacement is the area under the graph

Question 27

Write the equation for acceleration in algebraic form.

Answer 27

a = 🔺v/🔺t

Question 28

What do the letters suvat stand for in the equations of motion?

Answer 28

s = displacement u = initial velocity v = final velocity a = acceleration t=time taken

Question 29

Write the four suvat equations.

Answer 29

s = ut + 1/2at^2 s = 1/2(u+v)t v = u+at v^2 = u^2 +2as

Question 30

Define stopping distance

Answer 30

the total distance travelled from when the driver first sees a reason to stop, to when the vehicle stops

Question 31

Define thinking distance

Answer 31

the distance travelled between the moment when you first see a reason to stop to the moment when you use the brake

Question 32

Define braking distance

Answer 32

the distance travelled from the time the brake is applied until the vehicle stops

Question 33

What does free fall mean?

Answer 33

when an object is accelerating under gravity with no other force acting on it