Explanation:
Below is an attachment containing the solution.
Given that,
Initial velocity , Vi = 0
Final velocity , Vf = 40 m/s
Acceleration due to gravity , a = 9.81 m/s²
Distance can be calculated as,
2as = Vf² - Vi²
2 * 9.81 *s = 40² - 0²
s = 81.55 m
For half height, that is, s = 40.77m
Vf= ??
2as = Vf² - Vi²
2 * 9.81 * 40.77 = Vf² - 0²
Vf² = 800
Vf = 28.28 m/s
Therefore, speed of roller coaster when height is half of its starting point will be 28 m/s.
Check the attached file for the answer.
The correct answer is A. 32.5
Mechanical advantage is the ratio of force that is input into a machine to the force output.
Mechanical advantage of a wheel and axle is calculated by dividing the radius of the wheel by that of the axle.
MA=R/r where R is the radius of the wheel and r is the radius of the axle.
Substituting for the values in the question gives:
MA=26cm/0.8cm
=32.5
