Any help is appreciated!
Gold has a density of 19.3 g/cm3. Do you think you could carry 2.40 cubic ft (rhetorical--don't answer)? How many pounds does 2.40 cubic feet of gold weigh? [453.6 g = 1 lb, 2.54 cm = 1 in, and 1 ft = 12 in.]
7.42e-2
A scientific oven is programmed to change temperature from 51.4 ºF to 207.4 ºF in 1.50 minute(s). Express the rate of change in degrees Celsius per second.
-1.16
A bug is observed to travel 72 cm in 7.5 seconds. What is the bug's speed in miles per hour?
.21
Thank you!
a isn't even close. Show your work and I'll find the error.
b is close but I obtained 1.7 or thereabouts.
c. 0.214 is the factor for cm/sec to mph. You still must multiply by cm/sec which is 72/7.5.
thanks! all i did for a was change 2.4 by converting it in the manner they said, from feet to inches, inches to centimeters. same with 19.3. i changes it from grams to pounds.
something tells me you divided instead uf multiplying somewhere. In problems like this, be sure to keep track of the units, so you cancel out the ones you don't want.
As for you answer of .00742 lbs, even a cursory sanity check would give a clue that it's bogus. Gold is heavy. Could you lift a cubic foot of it? I doubt it. So, on to the calculations. You want to convert ft^3 to lbs, knowing the various equivalents.
2.4 ft^3 * 12^3 in^3/ft^3 * 2.54^3cm^3/in^3 * 19.3g/cm^3 * 1lb/453.6g = 2892 lbs
Great! Thank you!
Hey, no problem. It was a real epiphany for me when I took physics, when I found out that units could be canceled just like numeric factors.
To calculate the weight of gold in pounds from its volume in cubic feet, we need to convert the units using the given conversion factors.
1 ft = 12 inches
Therefore, 2.40 cubic ft = 2.40 ft * 12 inches/ft = 28.80 inches
1 inch = 2.54 cm
Therefore, 28.80 inches = 28.80 inches * 2.54 cm/inch = 73.15 cm
Now, we need to convert the volume from cm^3 to g.
Gold density = 19.3 g/cm^3
Weight of gold = volume * density
Weight of gold = 73.15 cm^3 * 19.3 g/cm^3 = 1,412.595 g
Next, we need to convert the weight from grams to pounds using the given conversion factor.
453.6 g = 1 lb
Weight of gold in pounds = 1,412.595 g * 1 lb/453.6 g = 3.113 lbs
So, 2.40 cubic feet of gold weighs approximately 3.113 pounds.
For the second question, we need to convert the temperature from Fahrenheit to Celsius and the time from minutes to seconds.
Change in temperature = 207.4 ºF - 51.4 ºF = 156 ºF
To convert Fahrenheit to Celsius, we use the formula: °C = (°F - 32) * (5/9)
Change in temperature = (156 ºF - 32 ºF) * (5/9) = 124 ºC
Now, we need to find the rate of change in degrees Celsius per second.
1 minute = 60 seconds
Rate of change = change in temperature / time
Rate of change = 124 ºC / 1.50 minutes * 60 seconds/minute = 496 ºC/second
Therefore, the rate of change in degrees Celsius per second is 496 ºC/second.
For the third question, we need to convert the distance traveled from centimeters to miles, and the time from seconds to hours.
Distance traveled = 72 cm
To convert centimeters to miles, we use the conversion factor: 1 mile = 160934.4 cm
Distance traveled = 72 cm * 1 mile/160934.4 cm = 0.00044637 miles
Time = 7.5 seconds
To convert seconds to hours, we use the conversion factor: 1 hour = 3600 seconds
Time = 7.5 seconds * 1 hour/3600 seconds = 0.00208333 hours
Now, we can calculate the speed in miles per hour.
Speed = distance traveled / time
Speed = 0.00044637 miles / 0.00208333 hours = 0.2142 mph
Therefore, the bug's speed is approximately 0.21 miles per hour.