Answer:
D. 59.23 m
Explanation:
Given that:
initial height [tex]h_i[/tex] of the roller coaster = 200m
speed (v) = 40 m/s
use conservation of energy between starting height and top of loop
[tex]m*g*h_i = \frac{1}{2}mv^2 + m*g*h_f[/tex]
where
[tex]h_f[/tex] i.e the final height = 2R
R = radius of the loop
Then
[tex]m*g*h_i = \frac{1}{2}mv^2 + m*g*2 R[/tex]
Divide both sides with m; we have :
[tex]g*h_i = \frac{1}{2}v^2 + g*2 R[/tex]
[tex]9.81*200 = \frac{1}{2}*40^2 + 9.81*2 R[/tex]
1962 = 800 + (9.81 )(2R)
1962 -800 = (9.81 )(2R)
1162 = 19.62 R
[tex]R = \frac{1162}{19.62}[/tex]
R = 59.23 m