2012/2013Name: - class: - date: - / /

'-- ~~_Work sheet 1

Mass and Weight

Mass and weight are two important quantities in science. It is easy to confuse them. Theseexercises will help you to learn the difference between them.

1. The mass of an object is measured in grams (g) or Kilograms (kg).Here is a listof objects.

Bus mouse car cow girl house bookThe table below shows the mass of each of these objects, but which is which?Write the names of the objects in the second column of the table, to show theirmasses; then calculate the weight of each one ....

Mass Object Weight20 g !Y)OU.5€... 0.2. to

500 g bOi>~ 5N30 kg Girl 3nof..J

250 kg C£>w 2,500"-.1800 kq tar 1S000 N

5000 kq Bus SOCWN100 000 kq H()()~ I\?OO 000 /J

2. To find out the weight of an object, we multiply its kg by 10. This is because theEarth's gravity pulls on every kg of mass with a force of 10 N.

Weight (in N) = mass (in kg) x 10A baby had a mass of 3.0 kg when he was born. Calculate the baby's weight.

~= rn~>fxiO= 3 x10= 30~

3. Write mass or weight next to each statement in the second column of thistable

statement Mass or weightThe force of qravitv actinq on an object we..t.';h tMeasured in kiloorarns ma.ssGets much less if you go to the Moon W€Afji1fcan be represented by a force arrow W~'qktMeasured in newtons (N) VJ~jl1,tAdd 50 q of salt to 1 kg of water WI QS,s

Stays the same even if you are far out in space mas5 apples are about 5N WLI'qht

"

Chapter 1 - Measurements Hany EI-Gezawy Page 1

Name: - class: - date: - / /

Work sheet 2~---------------------------Measurements

For measuring short intervals of time (when each period is the same), multiple measurements can betaken

Periodic time = Time/n

Complete:-

1. ~.cal.11Aierror happens when you have an error in reading due to the angle of view.

2. The time of 30 swings of a pendulum is 20 seconds, so the time of each one equals 20":'.$:....0.•.66 530

3. The time of 20 swings of a pendulum is 30 seconds, so the time of each one equals .~ ....::::..~:,.5 s20

4. A piece of cotton is measured between twopoints on a ruler (from 2 cm to 15 cm). When pen<r ItSixturns~ofcottonthe length of cotton is wound closely arounda pen, it goes round six times; So thedistance once round the pen is 00

\ ~CrI\ -::: 2.16 emG

5. The weight of 50 apples is 50 N, so the average weight of each apple is ~.t-:!.. and the averagemass of each one of them is 0·1 K3 ( o,1.~ = 1(03)

6. If the mass of 20 similar marbles is 2 kg, so the mass of one marble is 1,09 gram.{fo:=.o.1. ~7. If the thickness of 200 pages note is 2 cm, so the thickness of only one page is Q.~.o.1.Cm8. If the reading of a micrometer to measure the thickness of a wire is 2.93 mm, and the zero

error was 0.1 mm, so the true thickness is L..2. Cf3 - 0 .1J = 2. S3

Choose ~ The diagram shows one method of measuring the diameter of a beaker.

~/' "3·S--?S

~ - 5·5> 4 5CY>1

ruler

wooden block

beaker

bench

What is the diameter of the beaker?

@4.5cm B 5.0cm C 5.5cm D 8.0cm

Chapter 1 - Measurements Hany EI-Gezawy Page 2

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2012/2013

Name: - class: - date: - / /

Measurements

Density is the mass of unit volume

Density = mass/volume

Please answer all questions as completely as possible showing all calculation and work needed. Alsodon't forget to include your units!

1. Rearrange the density equation for the following:

Mass = dCCfl~ i+'f Volume = h"a sSVolume de¥'\~\-r

2. Calculate the density of a material that has a mass of 52.457 g and a volume of 13.5 ern",

denslrN s; VraSS = 52. ~57!IS.S:= ~ ~S>~ j/c-¥l( volvt'ne-

3. A student finds a rock on the way to school. In the laboratory he determines that the volume ofthe rock is 22.7 mL, and the mass in 39.943 g. What is the density of the rock?

def1S\N z: roo s ~ == 39. Q'-t3- ( v"o\jru. 22.1-

4. The density of silver is 10.49 g/cm3. If a sample of pure silver has a volume of 12.993 crrr',what is the mass?

N CcS5 -::= dev:.s·~ ')(\ft)lv~ == 1\ a .~q X' I2 , CfC( 1_ I36 . 29 .3

5. What is the mass of a 350 crrr' sample of pure silicon with a density of 2.336 q/crn '?

Ma~,s = deYls'7 X VO\Umtl =- z, 336 X '3 50:= ~ I-':;,b !36. Use the information in this table to decide which crown is gold, which is silver and which is a

mixture (impure)?

~ (~ (2))~ IO~5\\- \s si\ve.-

~ (Gb...>~ ~) = \cy/?,r.f- 'I So Gotd

f<J

GolJ (1 L" i~<:£===================rm=~_U_~__D__~ ~ _

Chapter 1 - Measurements Hany EI-Gezawy Page 3