This question is all about dimensional analysis. The whole idea behind dimensional analysis is that you multiply a starting value with different conversion factors to cancel out units you don't want to tern the value into the units that you do want. The conversion for yards to feet can be written as 3 feet/yard (this is the conversion factor it can be written as 3feet/1yard or 1yard/3feet, it depends on what you are starting with). If you start out with yards and and want to go to feet you have to multiply the number of yards by 3feet/yard so that the yards cancel out leaving you with feet. If start out with feet and want to go to yards you divide the number of feet by 3feet/yard so that the feet cancel out and you are left with yards.
In your question Tom is trying to go from feet to yards. Therefore he has to divide the number of feet by 3feet/yard to get feet to cancel out. His mistake was that he multiplied by 3feet/yard instead of divide by 3feet/yard. The correct way do it is divide 379 feet by 3feet/yard to get 126.33 yards.
Let me know if anything is unclear to you in the comments. This is a very important skill to learn since this is the basis of many high school and college science classes.
I hope this helps.
This graph is growing exponentially, 0.5 more each time at every point
<span>Acceleration of a passenger is centripetal acceleration, since the Ferris wheel is assumed at uniform speed:
a = omega^2*r
omega and r in terms of given data:
omega = 2*Pi/T
r = d/2
Thus:
a = 2*Pi^2*d/T^2
What forces cause this acceleration for the passenger, at either top or bottom?
At top (acceleration is downward):
Weight (m*g): downward
Normal force (Ntop): upward
Thus Newton's 2nd law reads:
m*g - Ntop = m*a
At top (acceleration is upward):
Weight (m*g): downward
Normal force (Nbottom): upward
Thus Newton's 2nd law reads:
Nbottom - m*g = m*a
Solve for normal forces in both cases. Normal force is apparent weight, the weight that the passenger thinks is her weight when measuring by any method in the gondola reference frame:
Ntop = m*(g - a)
Nbottom = m*(g + a)
Substitute a:
Ntop = m*(g - 2*Pi^2*d/T^2)
Nbottom = m*(g + 2*Pi^2*d/T^2)
We are interested in the ratio of weight (gondola reference frame weight to weight when on the ground):
Ntop/(m*g) = m*(g - 2*Pi^2*d/T^2)/(m*g)
Nbottom/(m*g) = m*(g + 2*Pi^2*d/T^2)/(m*g)
Simplify:
Ntop/(m*g) = 1 - 2*Pi^2*d/(g*T^2)
Nbottom/(m*g) = 1 + 2*Pi^2*d/(g*T^2)
Data:
d:=22 m; T:=12.5 sec; g:=9.8 N/kg;
Results:
Ntop/(m*g) = 71.64%...she feels "light"
Nbottom/(m*g) = 128.4%...she feels "heavy"</span>
A is the 4
B is the 5
and C is also 4.
A is always the number in front of x^2. B is always the number i front of the normal x, and C is the number that is on the other side of the equal sign!
40,000 is 10 times as much as 4,000
