Units Prefixes and Scientific Notation TEST

1.	Give the SI units for the following physical quantities

a) length,

b) mass,

c) acceleration,

d) velocity,

e) density,

f) impulse (6)

a) metre

b) kilogram

c) metres per second squared

d) metres per second

e) kilogram per cubic metre

f) Newton second

2.	A bus is travelling due North at 12 ms-1, a girl runs West across the bus at 3ms-1, suddenly she is sick and projects this at 2 ms-1 at an angle of 30o North of West. What is the resultant velocity of the sick?

0

The resultant velocity of the sick is

13.8 ms –1,

14ms –1 @ 20o W of N.

Do not use too many sig fig and be accurate in your drawings.

3.	If a force of 1N is applied to a 3 kg mass what acceleration can this produce?	(2)

This question is checking your ability to stick to a significant number of figures.

The acceleration is 0.3 ms –2.

You must not write any more than one sig. fig. as this is the level of accuracy given in the question.

4.	A leaf of mass 0.1g feels a frictional force of 948μN as it falls from a tree. What is its acceleration as it falls? Include a free body diagram of the leaf.	(5)

This question is checking that you are aware of prefixes used in Physics.

m = 0.1g = 0.110 –3 kg	W = mg W = 0.110 –39.8 W = 9.810 –4N
F=9.4810 –4 N W=9.810 –4 N	Unbalanced force = W-F F=0.3210 –4N F=ma 0.3210 –4 = 0.110 –3a a=0.32ms –2

5.	Express the following in scientific notation.

a) 50mA	a) 5.010 –3 A
b) 0.3nF	b) 3.010 –5 F
c) 200s	c) 2.0010 2 s
d) 45F	d) 4.510 –5 F

Uncertainties Revision TEST

1	a)	Find the percentage error in the following display.	(2)

0	10	20	30	40	50	60

(½ scale division reading x 100%	(1)

5/37 x 100% =13.5%	(1)

Probably ought to round to 10% or 14% at the most. NO MORE SIG FIG

2.	Give an example of the following errors,

i)	Random uncertainties, Fluff on a wheel, wind, door opening during an experiment etc.	(1)

ii)	Systematic effects. Zero errors on equipment, bad design ( give egs) etc.	(1)

3.

Time/s	1.58	1.55	1.59	1.56	1.56	1.58

Calculate the percentage error in these results.

mean =x/n

1.58+1.55+1.59+1.56+1.56+1.58= 9.42

mean average =1.57	(1)

approx. random error = (max-min) no. of readings

= (1.59-1.55)/6 =(0.04)6 =0.0067	(1)

% uncertainty = a.r.e./ mean 100%

% uncertainty= 0.00671.57100% = 0.42%	(1)

4.	What must you be aware of whenever you are making a measurement?	You must be aware that any experiment is liable to error, just look for them!	(1)

5.	How can you reduce the error that you make in your experiments? You can reduce your error by taking many readings, but this will not help improve the accuracy if you have a systematic error.	(1)

6.	What is the best measurement that we can hope for? The best measurement that we can hope for is that the mean value is close to the “true” value.	(1)

7.	Draw a diagram illustrating the effects of a systematic error in a set of results.

x x x xxx x x xx x or If the arrow represents the true value the x represent your readings.	(1)

8.	Estimate the scale-reading uncertainty in the following

a) a voltmeter reading of 0.12V (0.01/0.12) 100% = 8.3%	(2)

b) an ammeter reading of 1.0mA	(0.1/1.0) 100% = 10% (2)

9.	Find the absolute uncertainty in the following readings. (4)

Speed /ms –1	0.97	0.92	1.07	1

mean =x/n

0.97+0.92+1.07+1= 3.96

mean average =0.99	(1)

approx. random error = (max-min) no. of readings

= (1.07-0.92)/4 =(0.15)/4 =0.0375	(1)

% uncertainty = a.r.e. mean 100%

% uncertainty= 0.0375/0.99100% = 3.8%	(1)

b)	What error has been made when recording the above results?	However, as one of the results is recorded only to one sig fig this level of accuracy ought to be used throughout.	(2)

10.	The following results were obtained from an experiment.

distance = 1.00 0.01m,	time = 0.16 0.02s

Calculate the speed from these results and express it in the form final valueuncertainty.	(3)

Find the largest percentage error in the measurements

0.01/1.00x100% = 1.0%

0.02/0.16 x 100% = 12.5%

The error in the speed calculation will be 12.5%

speed = distance/time

= 1.00/0.16

= 6.25 ms –1

Speed = 6.25 ms –1 10%

or

Speed = 6.3 0.8 ms –1 (where 0.78 is 12.5% of 6.25)

Introduction to Our Dynamic Universe Test

Produce a table with the headings Scalar and Vectors and see how many scalars and vectors you can add to the table in 60.0s. Two marks for a vector, one mark for a scalar.

Scalar	Vector
Time	Displacement
Energy	Velocity
Mass	Acceleration
Length	Momentum
Distance	Force
Speed	Field strength
Area	Impulse
Charge
Work
Current
Voltage
Resistance
Equivalent Dose
Activity
Frequency
Volume
Temperature
Power
Latent heat
Radius etc….

Three vectors are each 120 apart and directed away from an object. One is 15.0 N, one 25.0N and one 20.0 N, what is the resultant force on the object?

25 N 15 N 20 N

=30 to the vertical

8.7 N @ 30 to the vertical

A 25 N force acts on a shopping trolley handle at an angle of 50 to the horizontal, state the horizontal and vertical components of this vector.

25 N 40 50

horizontal 25cos50	25sin40	(1)

vertical	25sin50	25cos40	(1)

State the measurements that would be required to determine the acceleration of a trolley as it rolled down a slope? Draw a diagram of the set up, state the measurements, equipment and formulae you would use.

Measurements	Calculations
t1 time to pass first light gate
t2 time to pass second light gate
t3 time between light gate
length of mask

or if only one light gate then t2 = time for back end of the mask to pass through the light gate and t3 to equal the time between the front and back ends of the mask going through the light gate.

State the Equations of Motion.	(1 for each equation) no additional marks for rearranging!

Prove as many of the Equations of Motion as possible.

time (s) velocity (ms-1) v u t 0