jen

How much time should be spent on each question during an exam?

exam is 75 minutes long and there are 128 questions 

I was being proctored for an exam today and they said for the next time they need to be able to see my task bar and I have to share it? I already am sharing my screen with them so what else does this do? What is the task bar and what do they not see when my screen is already shared?

A block with a volume of 15.2 m3 is completely submerged in freshwater. The density of freshwater is 1000 kg/m3.

 Use Archimede’s principle to calculate the buoyant force acting on the block when submerged.

An object with a weight of 1258 N experiences a 215 N buoyant force when submerged in water.

 Calculate the apparent weight of the object.

A ball with a volume of 17.8 m3 and density of 178 kg/m3. 

Find the mass of the ball.

I get what osmosis is and how it work (I just did an experiment with it)...but why is it important to know about it and why it works? Why is ut important to be able to answer questions about it?

in your class, you have scores of 66, 83, 79, and 86 on the first four of five test. to get a grade of C, The average of the first five test scores must be greater than or equal to 70 and less than 80. 

a) solve an inequality to find the least score you can get on the last test and still earn a C? 

b) what score do you need if the fifth test counts as to test? 

Betsy, A recent retiree, requires $5000 per year in extra income. She has $60,000 to invest in can invest in B-rated Bonds paying 13% per year or in a certificate of deposit (CD) paying 3% per year. how much money should be invested in each to realize exactly $5000 in interest per year? 

The amount of money invested at 13%-

The amount of money invested at 3%-

Suppose you have entered and 86 mile biathlon that consist of a run and a bicycle race. during your run, your average velocity is 8 miles per hour, and during your bicycle race, your average velocity is 23 mph. you finish the race in 7 hours. what is the distance to the run? what is the distance of the bicycle race? 

An oil tanker can be emptied by the main pump in 5 hours. An auxiliary pump can empty the tanker in 12 hours. If the main pump is started at 4 PM​, when should the auxiliary pump be started so that the tanker is emptied by 8 PM​?

the auxiliary pump should be started at _:_ PM? 

Because of Venus’ proximity to the sun and its thick, high-pressure atmosphere, it’s temperature can rise to 860 F. Express this temperature in degrees Celsius. 

Temp- C

the temptation of the moons surface can reach 117 C when exposed to the sun and can cool to -163 C when facing away from the sun. Express this temperature change in degrees Fahrenheit. 

The total mass of fresh water on earth is 3.5 x 10^19 kg. suppose all this water has a temperature of 10 C. supposed the entire energy output of the sun is used to bring all the earths freshwater to a boiling temperature of 100 C, after which the water is completely vaporized. How much total energy must be added to the fresh water through heat in order to raise the temperature to the boiling point and vaporize it?

Q1: Energy needed to change the temperature from 10 to 100 to bring it to boiling point= 1.32 x 10^25JQ2: Energy to change it from a water to steam=7.90 x 10^25 JQtotal=

The United States Bullion Depository at Fort Know, Kentucky, contains almost half 1, million standard mint gold bars, each with a massive 12.4414 kg. Assuming and initial bar temperature of 5 C, each bar will now if it absorbs 2.5 MJ I have energy transferred by heat. If the specific heat capacity of gold is 129 J/kg*C and the melting point of gold is 1063 C, calculate the latent heat Fusion of Gold. 

Lf(gold)=

The lowest temperature measured on the surface of a planetary body in the solar system is that of Triton, The largest of Neptunes moons. The surface temperature on this distant moon can reach a low of -235 C. suppose an astronaut brings a water bottle containing .5 kg of water to Triton. The water temperature decreases until the water freezes, then the temperature of the ice decreases until it is in thermal equilibrium with Triton at a temperature of -235 C. if the energy transferred by heat from the water to Triton is 471 kJ, what is the value of the waters initial temperature? (water to ice phase change)

waters initial temperature-

The total mass of fresh water on earth is 3.5 x 10^19 kg. suppose all this water has a temperature of 10 C. supposed the entire energy output of the sun is used to bring all the earths freshwater to a boiling temperature of 100 C, after which the water is completely vaporized. How much total energy must be added to the fresh water through heat in order to raise the temperature to the boiling point and vaporize it?

Q1: Energy needed to change the temperature from 10 to 100 to bring it to boiling point=

Q2: Energy to change it from a water to steam=

Qtotal=

The water in the Arctic Ocean has a total mass of 1.33 x 10^19 kg. The average temperature of the water is estimated to be 4 C. what would the temperature of the water in the Arctic Ocean be if the energy produced in 1000 years by the worlds largest plant if 4.2 x 10^20 J of energy was added to it over the time period? (absorb energy)

oceans final temperature-

there is a little island off the shore of Brazil where the weather is extremely consistent. From 1911 to 1990, the lowest temperature on the island was 18 C (64F) in the highest temperature was 32 C (90F). it is now that at the lake with in in a standard can of soft drink absorbs 20.8 kJ of energy when its temperature increases from 18 C to 32 C. if the soft drink has a massive .355 kg, what is it specific heat capacity? (absorb energy)

C soft drink- 

in 1994, to commemorate the 200th anniversary of a beverage Company, a giant bottle was constructed and filled with 2250 kg of the companies lemonade. suppose the lemonade has an initial temperature of 28 C when 900 kg of ice with the temperature of -18 C is added to it. what is the lemonades temperature at the moment the temperature of ice reaches 0 C? Assume that the lemonade has the same specific heat capacity as water. (mixture)

answer-

in 1992, a team of firefighters pumped 143 x 10^3 kg of water in less than four days. What a mass of wood can be cooled from a temperature of 280 C to one of 100 C using this amount of water? assume that the initial temperature of the water is 20 C and that all of the water as a final equilibrium temperature of 100 C, but that none of the water is vaporized. Use 1700 J/kg*C for the specific heat capacity of wood. (mixture) 

answer-