a 230 kg roller coaster reaches the top of the steepest hill with a speed of 6.2 km/h. It then descends the hill, which is at an angle of 45 and is 51.0 m long/ What will its kinetic energy be wehn it reaches the bottom

81.619 kJ

Explanation:

Given

Mass of roller coaster is

It reaches the steepest hill with speed of

Hill to bottom is 51 m long with inclination of

Height of the hill is

Conserving energy to get kinetic energy at bottom

Energy at top=Energy at bottom

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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