I believe the correct answer is A) From crest to crest.
~Silver
<em>Answer:</em>
<em>The Atmosphere.</em>
<em>Explanation:</em>
<em>The Atmosphere contains all of the planets air, And without air we can't breathe so I think this would be a good answer for you to choose, have a nice day</em>
Answer: B. Concrete
Explanation:
Let N = reacting force pressing the bodies in context together (units in Newtons),
The question stated that the force pressing the two mounted/stacked objects together is equal to the weight of the object on top.
We need to start by finding the weight of the piece of wood.
friction is given by
f = μN
The value of f is 22.5,
and from the chart reference the coefficient of friction between wood and stone, μ is 0.30.
22.5 = 75. 0.30
Putting the values into the equation: 22.5 = 0.30N.
Divide both sides by 0.30 to find the value of N:
N= 22.5/0.3 = 75
Now that the piece of wood will be placed on another surface, its weight of 75 Newton is the force pressing the two bodies together.
To determine the new surface, you should find the new coefficient of friction by using the new value of the force of friction given 46.5:
46.5 = µ(75).
Divide both sides by 75 to isolate μ.
The refer chart also indicates that the coefficient of friction equals 0.62 between wood and concrete, so the new surface corresponding to 0.62 is the concrete, which is (B).
Answer:
Athlete A
Explanation:
Power is the rate of doing work and it is calculated as follows:
Power = work done/time taken = mgh/t
(for work being done against gravity)
So for athlete A
P = (100 kg * 9.8 N/kg* 0.6m)/0.5 s = 1176 W
For athlete B
P = (150 kg * 9.8 N/kg* 0.6m)/1 s = 882 W
For athlete C
P = (200 kg * 9.8 N/kg* 0.6m)/2 s = 588 W
For athlete D
P = (250 kg * 9.8 N/kg* 0.6m)/2.5 s = 588
