







The mass of a length of tree trunk 
20171113 

From SM: What is the mass of a length of 1m of trunk a tree trunk of uniform cross section of area 0.5 sq.m is made of wood of relative density 0.8? Answered by Penny Nom. 





Cubic centimeters, milliliters and grams 
20130926 

From Laura: How do I find the volume of a cube with dimensions of .78 cm, .3 cm and .22 cm? Then find the volume in ML and the mass if filled with water? Answered by Penny Nom. 





A water tank is in the shape of a truncated cone 
20120308 

From Victoria: Suppose you have a water tank in the shape of a truncated cone. The larger diameter is K, the smaller diameter is K/2, and the height is also K (all measured in meters). The force of gravity on an object of mass, m, is F=9.8m (measured in Newtons). The density of the water is 1000 kilograms per cubic meter. What is the volume of the tank and how much mass will the tank have when it is full? Answered by Penny Nom. 





e = m c^2 
20091209 

From Jim: Please explain the following formula:
E=MC2 (squared) Answered by Robert Dawson. 





Apparent Weight in salt water 
20090606 

From Rob: If an object weighs 100kg in air how much will it weigh when suspended in salt water?
Is there an easily used conversion calculation? Answered by Janice Cotcher. 





Unit Conversion for Force and Mass 
20090508 

From Ray: Good Day! I was confused about lbm and lbf and slug. I knew that lbm is a unit
for mass and lbf is a unit for weight. my problem is some books follow this
relationship where lbf=(lbm times the gravitational pull) which is 32.2 ft/(s^2)
while other books treat lbm=lbf. other books also treat lbm=(lbf times 32.2)...
which is correct?
Is 1kg=2.205 lbm or 1kg=2.205lbf?
Is 1BTU=778.16 lbfft or 1BTU=778.16 lbmft?
what is the relationship of slug on these two, lbm and lbf? Answered by Janice Cotcher. 





The amount of material remaining on a reel 
20090304 

From James: Question from james:
I am after a standard calculation so that after each usage of the Reel I can get the Remaining Quantity in kilos left on the roll
below is an example of roll
THICKNESS: 30 MICRON
REEL WIDTH: 7.5 CM
REEL DIAMETER: 76 CM
REEL WEIGHT: 7.13 KILOS
The core centre has a 9cm diameter, the weight of the roll is excluding the core , and after each use the diameter of the role is measured.
I am a factory supervisor working on project and need this calculation info for template.. Thanks James Answered by Harley Weston. 





557 mL of benzaldehyde 
20080828 

From Kara: Calculate the mass of 557 mL of benzaldehyde. The density of benzaldehyde is 1.04 g/mL. Answered by Penny Nom. 





Net weight 
20080523 

From Leticia: Hello, My name is Leticia,
I am having trouble with Net weight and I need your help.
When I am in class my friends answer questions that they say are easy,but I have no clue what's happening, we are going to have a test soon so please send me fast. Answered by Janice Cotcher. 





Volume, mass and density 
20070914 

From Nathan: I have a sample of material that is 10cmx10cmx5cm and has a mass of 29 grams. How many grams would a sample of the same material that was 96cmx188cmx5cm be? Answered by Penny Nom. 





Is it platinum or silver? 
20070914 

From Jordan: In Chemistry we are doing a lot of problems that are much more math related than anything. One of my questions reads: A certain medallion has a mass of 55.64 g. When placed in 75.2 mL of water in a graduated cylinder,
the water level rises and then reads 77.8 mL.
Is the medallion made of platinum (D=21.4 g/mL) or silver (D= 10.5 g/mL)? Answered by Penny Nom. 





Converting mass of sand to volume (a sand ceremony) 
20070521 

From Linda: I'm getting married. We are having a sand ceremony. The empty bottle we are using holds 800ml. I have bags of colored sand. Each bag is 30g. There is 7 people participating in this ceremony. What I need to find out is how many grams of sand i need for 7 people to participate to fill this jar. Answered by Penny Nom. 





Friction of a skier 
20070324 

From William: An olympic skier moving at 20.0 m/s down a 30 degree slope encounters a region of wet snow and slides 145m before coming to a halt. What is the coefficient of friction between the skis and the snow? Answered by Stephen La Rocque. 





Density 
20070209 

From Judy: How do I calculate the mass in grams of 125mL of chloroform when d=1.49g/mL. Answered by Stephen La Rocque. 





The density of an irregular wooden block 
20070130 

From Carlos: I'm trying to help my son but I don't really have too much knowledge about this topic. he is been asked to convert 10 milliliter to gram, I think that since 1 g = 1ml the answer will be 10 g also there is another question of how of the density of an irregular wooden block is affected if: a) the center is hollow: b) the block is not completely submerged when determining the volume. Answered by Stephen La Rocque and Penny Nom. 





3.253 cubic meters of water 
20061031 

From Elaine: a tank full of water that has a volume of 3.253 cubic meters would have a mass of? Answered by Penny Nom. 





If a person who weighs 270 pounds on Earth 
20060510 

From Chloe: If a person who weighs 270 pounds on Earth weighs 45 pounds in space, how much would a person weigh in space who weighs 132 pounds on Earth? Answered by Stephen La Rocque and Penny Nom. 





How much does 1300cc of liquid weigh? 
20060428 

From Debra: How much does 1300cc of liquid weigh, and how is the formula equated? Answered by Stephen La Rocque. 





Density 
20030219 

From Rob: What is the formula for converting cubic feet to pounds? (with any substance) Answered by Penny Nom. 





A two stage rocket 
20021126 

From Hoda: a two stage rocket accelerates in free space by ejecting fuel at a constant relative speed , v(ex). the full fuel load makes up 80% of the initial mass of the entire two stage rocket . the rocket accelerates from rest until at the end of the first stage when 75% of its fuel has been burnt. find an expression for the speed of the rocket at the end of the first stage in terms of v(ex). Answered by Claude Tardif. 





Mass of the earth 
20000221 

From Terry Broughton: My name is terry i am 15 my question is how much does our planet earth weigh ? Answered by Chris Fisher and Harley Weston. 

