a. The temperature of the motor after t minutes is: T(t) = 20 + 200e^(-0.11t)
b. The temperature of the motor after 20 minutes is approximately 89.6°F.
Part (a)
The equation is:
ln(T-20)/200=-0.11t
To solve for T, we can exponentiate both sides of the equation:
T-20 = 200e^(-0.11t)
Adding 20 to both sides, we get:
T = 20 + 200e^(-0.11t)
Therefore, the temperature of the motor after t minutes is:
T(t) = 20 + 200e^(-0.11t)
Part (b)
To find the temperature of the motor after 20 minutes, we can simply substitute t = 20 into the equation for T(t):
T(20) = 20 + 200e^(-0.11*20) ≈ 89.6°F
Therefore, the temperature of the motor after 20 minutes is approximately 89.6°F.