Question

A computational model predicts the speed of a roller coaster car at different heights given its speed at the lowest height of its journey, which is at ground level. The speed at the lowest point is 30 m/s. What is the prediction for its speed when it is at a height of 20 m?

A. 22.5 m/s
B. 37.5 m/s
C. 18.8 m/s
D. 15.9 m/s

Answer 1

the answers, the correct one is A v= 22.5 m/s

Step-by-step explanation:

We can solve this problem using the concepts of conservation of mechanical energy

Starting point. Lowest point of the trajectory

Em₀ = K = ½ m v₀²

Final point. When it is at a height of y = 20 m

`Em_(f)` = K + U = ½ m v² + mg y

how energy is conserved

Emo = Emf

½ m v₀² = ½ m v² + m g y

v² = v₀² + 2 g y

let's calculate

v²2 = 30 2 + 2 9.8 20

v² = 508

v²= ra 508

v² = 22.54 m / s

When checking the answers, the correct one is A