Answer: 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

Answer:
Explanation: Here we have given a direct equation . There for no need to worry .
P = I²×R
P = (12)² ×100
P = 14400W = 14.4 kW
For second one
P = I² ×R
200 = I²×150
I = √200/150
I = 1.15 A