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mickeymouseho
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Homework Statement
Figure 4 shows a partial profile of a roller-coaster ride. Friction and air resistance are negligible. Determine the speed of the coaster at position C if the speed at the top of the highest hill is (a) zero and (b) 5.00m/sFigure 4 (description)
Point A is the highest point of the rollercoaster. It is 37.8m from the ground. Point B is the lowest point of the rollercoaster. It is 12.8m from the ground. Point C is the mid point of the roller-coaster. It is 17.8m from the ground.
*There are no loops
*From A, it curves downwards to B, then upwards to C
I apologize for not having a picture of this.
Homework Equations
E = 0.5mv^2
E = mgh
(sorry, not sure)
The Attempt at a Solution
I have no idea how to start this out...
E = mgh
= m x 9.8m/s^2 x 37.8m *keeping mass as a variable since mass is not given
= 370.44(mass)J
E = 0.5mv^2
370.44(mass)J = 0.5mv^2 *masses cancel out
square root of (370.44J / 0.5) = v
27.22m/s = v
The answer from the textbook: (a) 19.8m/s (b) 20.4m/s
I don't even know how to start out this problem.
EDIT:
for (a) h = 37.8m - 17.8m = 20m
Eg = mgh
= mass x 9.8m/s^2 x 20m
= 196 (mass) J
Ek = 0.5mv^2
196 (mass) J = 0.5mass x v^2 *masses cancel out
Square root: (196J/0.5) = v <- forgot to divide the gravitational potential energy by 0.5
19.8m/s = v
Got the answer for (a) but don't know how to figure out (b)...
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