Bob wants to measure the length of the red rectangle above. The ruler has 1 cm tick marks. Bob wants other scientists to have a
1 answer:
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Answer:
6005803.83105 short tons
Explanation:
The definition of density is , and the volume of a pyramid is (confusingly written on the proposal)
, so we can write:
Where s is the side of the base, being the area of that square.
We will write everything in S.I., and the best way to convert units is using conversion factors, for example, since 1m=100cm, we know that , and we can use this factor to convert anything written in cm to anything written in m. Example:
Here we just multiplied 500cm by something that is equal to 1 (as every conversion factor must), so <em>it's not doing anything but changing the units</em>.
We can use this tool like this:
Where we have used the fact that (<u>we can elevate any conversion factor to any number and they still will be 1</u>) and where we have placed strategically what is the numerator and what in the denominator so the units we don't want cancel out and the units we want appear.
Substituting then our values:
And now we will convert to short tons using two conversion factors at the same time:
Remember, their value is 1, and we place the units to cancel the ones we don't want and keep the ones we want, here Kg cancel out, and lb cancel out, leaving the short tones.
Answer:
570 N
Explanation:
Draw a free body diagram on the rider. There are three forces: tension force 15° below the horizontal, drag force 30° above the horizontal, and weight downwards.
The rider is moving at constant speed, so acceleration is 0.
Sum of the forces in the x direction:
∑F = ma
F cos 30° - T cos 15° = 0
F = T cos 15° / cos 30°
Sum of the forces in the y direction:
∑F = ma
F sin 30° - W - T sin 15° = 0
W = F sin 30° - T sin 15°
Substituting:
W = (T cos 15° / cos 30°) sin 30° - T sin 15°
W = T cos 15° tan 30° - T sin 15°
W = T (cos 15° tan 30° - sin 15°)
Given T = 1900 N:
W = 1900 (cos 15° tan 30° - sin 15°)
W = 570 N
The rider weighs 570 N (which is about the same as 130 lb).
