Berkeley Review Physics example 1.1b

[monkeyMD]

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No matter how many times I calculate this, I just cannot get the answer. It's off by x10. Why?

 

[SN2ed]

Thread moved. These types of questions belong in the MCAT Study Q&A forum.

 

[TwoPaddles]

No matter how many times I calculate this, I just cannot get the answer. It's off by x10. Why?

?mil/h = (2.906e-2 km/s)*(3.6e3s/1hr)*(1.0e3m/1km)*(1mil/1.6e3m) = 65.25 mil/hr

e represents *10^power ... in case you don't know

 

[drechie]

how do you do this "in your head" and without the gritty time consuming "math."

 

[NextStepTutor_1]

Use estimations to make the math simpler:

2.906e-2 ==> 3 e-2
3.6e3 ==> 4 e3
1.6e3 ==> 2 e3

mil/h = (2.906e-2 km/s)*(3.6e3s/1hr)*(1.0e3m/1km)*(1mil/1.6e3m) = 65.25 mil/hr

Thus, the answer becomes : (3e-2)*(4e3/1)*(1e3/1)*(1/2e3) = 60 miles/hr, which is close enough for all intents and purposes on the MCAT.