the power rating of an electric lawn mower is 2200 watts. if the lawn mower was used for 30 mins, and 650 Newtons of force was u
1 answer:
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Given Information:
Resistance = R = 14 Ω
Inductance = L = 2.3 H
voltage = V = 100 V
time = t = 0.13 s
Required Information:
(a) energy is being stored in the magnetic field
(b) thermal energy is appearing in the resistance
(c) energy is being delivered by the battery?
Answer:
(a) energy is being stored in the magnetic field ≈ 219 watts
(b) thermal energy is appearing in the resistance ≈ 267 watts
(c) energy is being delivered by the battery ≈ 481 watts
Explanation:
The energy stored in the inductor is given by
The rate at which the energy is being stored in the inductor is given by
The current through the RL circuit is given by
Where τ is the the time constant and is given by
Therefore, eq. 1 becomes
At t = 0.13 seconds
(b) thermal energy is appearing in the resistance
The thermal energy is given by
(c) energy is being delivered by the battery?
The energy delivered by battery is
Answer:
D) The heavier ball will have a higher temperature because the change of temperature is inversely proportional to mass.
Explanation:
As stated in the problem, the amount of heat released by each ball is
where
m is the mass of the ball
Cp is the specific heat of iron (so, it is equal for both balls)
is the change in temperature of each ball
In this problem, we are said that the amount of heat released by the two balls, Q, is the same. Cp is also the same: this means that the product must be the same for the two balls. So, the mass and the change in temperature are inversely proportional: therefore, the heavier ball will have a smaller change in temperature. And since both balls starts from the same temperature, 100 C, this means that the heavier ball will reach a higher temperature than the lighter ball.