1) 0N... friction opposes the motion of an object, since the block is at rest there is no motion thus no friction
2) F=ma
= (5.5kg)(30m/s)
=165 N
44 x 12. I got the 12 from the total of 12 months in a year.
44 > 40
x
12 > 10
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The way my teacher taught me how to estimate is look at the neighbor to 44 and 12. The only time 44 can become 50, is when the neighbor is 5 or up. Same thing for 12. Now, multiply 40 and 10.
40 x 10 = 400.
Therefore, your estimate is 400.
The real answer is 520 breaths.
