Bell Ringer

1
Bell Ringer

• What is the formula to calculate density?

2
Were going to solve this

• 1. You have gotten data from another student in
  the class. You have to calculate the density of
  a piece wood. All that you got from the other
  student is that it has a mass of 150 g and the
  measurements of 10 cm, 19 cm and 2 cm. What is
  the density of the wood?

Remember Density mass volume
19 cm
150 g
Density
2 cm
380 cm3
10 cm
0.395 g/cm3
Volume 10 cm x 19 cm x 2 cm Volume 380 cm3
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Next

• 2. You have taken measurements of various
  notebooks to see what school supplies you need to
  purchase for next year. You know that youll
  have to carry 4 notebooks each and each one will
  have a mass of 600 g. You have a lot of
  backpacks to choose from, but they are built for
  different amounts of stuff one holds 5 kg, one
  can take 4 kg, and the other will hold 3.4 kg.
  Which backpack would you choose to carry your
  daily notebooks?

Total mass
4 x 600 g
2400 g
1 kg 1000 g
2400 g 1
2400 g x 1 kg 1 x 1000 g
2400 kg 1000
2.4 kg
x



Any backpack will be fine, but Id pick the 4 kg
one because those classes also have books to go
with them.
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• 3. Youve decided to go fishing over the
  weekend. You know that you are fishing for
  tilapia, which have an average mass of 125 g.
  You want to make sure that you pick the right rod
  so that you can haul in your dinner. You have 4
  rods to choose from, each of which have different
  capacities 1.8 kg, 2.7 kg, 3.6 kg and 5.4 kg.
  Which rod should you choose?

125 g 1
1 kg 1000 g
125 kg 1000
0.125 kg
x
Any rod will be fine, but Id pick the 2.7 kg,
because who only ever catches Tilapia.
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• 4. You are traveling from Peasley to GHS for
  the football game. You have to be there in 18
  minutes (1080 seconds). The speed limit is 48
  kilometers per hour, and the distance between
  Peasley and GHS is 8.24 kilometers. Without
  speeding, is it possible to make it to GHS on
  time? (Hint Calculate how long it takes you to
  get from Peasley to GHS.)

How long you have.
1 hr 60 min
18 min
x
0.3 hr

8.24 km
x
hr 48 km

0.17 hr
How long you need.
So, yes, you would make it with time to spare.
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• 5. The density of lead is 11.3 g/cm3, and the
  density of silver is 10.5 g/cm3. If samples of
  each had volumes equal to 1 cm3, which would have
  the greater mass, and how much would the
  difference in mass be?

Density mass volume
a. Which would have the greater mass?
Density 11.3 g/cm3
Lead
Mass density x volume
Volume 1 cm3
Mass 11.3 g x 1 cm3 cm3
11.3 g
Density 10.5 g/cm3
Silver
Mass 10.5 g x 1 cm3 cm3
10.5 g
Volume 1 cm3
b. What would the difference in mass be?
11.3 g - 10.5 g 0.8 g