Measuring density: Measure the mass (in grams) of each mineral sample available to you. The mass of each sample is measured using a balance or electronic scale. Record mass on a chart.
Answer:
2,54 cm are equal to 1 inch
Explanation:
Doing the conversion:
![55[cm]*\frac{1[inch]}{2,54[cm]} =21,65[inch]](https://tex.z-dn.net/?f=55%5Bcm%5D%2A%5Cfrac%7B1%5Binch%5D%7D%7B2%2C54%5Bcm%5D%7D%20%3D21%2C65%5Binch%5D)
Answer:
Explanation:
Given
altitude of the Plane 
When Airplane is
away
Distance is changing at the rate of 
From diagram we can write as

differentiate above equation w.r.t time

as altitude is not changing therefore 

at 
substitute the value we get 

Answer:
Explanation:
Gravity pulls everything down at the same rate of 9.8 m/s/s. If you're looking for the normal force, which is the same as the weight of the object, we'll find that, just in case.
w = mg which says that the normal force/weight of an object is equal to its mass times the pull of gravity:
w = 4.0(9.8) so
w = 39N
My answer i believe is simply 250 Hz, because sounds or vibrations travel in 1 cycle/second, meaning the number of cycles, in your case 250, divided by the time,1 second, will ultimately be 250 Hertz. For every Cycle/second it will equal 1 Hz, so 250/1 = 250Hz