Out of the choices given, igniting the gas-air mixture supplies the heat for the hot reservoir in a car's engine. The correct answer is C.
We can substitute the given values into the equation for T, given the surrounding temperature T0 = 0, initial temperature T1 = 140, constant k = -0.0815, and time t = 15 minutes.
T = 0 + (140 - 0)e^(-0.0815*15) = 140e^(-1.2225) = 41.23°F
Answer:
24.07415 rpm
Explanation:
= Coefficient of friction = 0.63
v = Velocity
d = Diameter = 4.9 m
r = Radius = 
m = Mass
g = Acceleration due to gravity = 9.81 m/s²
Here the frictional force balances the rider's weight

The centripetal force balances the weight of the person

Velocity is given by

Converting to rpm

The minimum angular speed for which the ride is safe is 24.07415 rpm