Change of State and a Physical Change
Potential energy = (weight) x (height)
After the car has been raised 2.5 meters, it has
(11,000) x (2.5) = 27,500 Joules
MORE potential energy than it had before it was lifted.
That's the energy that has to come from the work you do to lift it.
Since no mechanical process is ever 100% efficient, the work required
to accomplish this task is <em>at least 27,500 joules</em>.
I'm actually going ahead in the book (DC Circuits) so this isn't really homework but I figured the tag was appropriate....the name of the chapter is Ohm's Law and Watt's Law.
<span>Problem: Calculate the power dissipated in the load resistor, R, for each of the circuits.Circuit (a): V = 10V; I = 100mA; R = ?; Since I know
V and
I use formula
P = IV: P = IV = (100mA)(10V) = 1 W.</span>
The next question is what I'm not sure about:
Question: What is the power in the circuit (a) above if the voltage is doubled? (Hint: Consider the effect on current).
What I did initially was: P = IV = (100mA)(2V) = 2 W
But then I looked at the answer and it said 4 W, then I looked at the Hint again. Then I remembered in the book early on it said "If the voltage increases across a resistor, current will increase."
So question is: When solving problems I have to increase (or decrease) current (I) every time voltage (V) is increased (decreased) in a problem, right? How about the other way around, when increasing current (I), you need to increase voltage (V). I'm pretty sure that's how they got 4 W, but want to make sure before I head to the next section of the book.
P = IV = (200mA)(2V) = 4 W
Answer:4. Two charged objects have a repulsive force of 0.080 N. If the distance separating the objects is tripled, then what is the new force? Explanation: The electrostatic force is inversely related to the square of the separation distance.
Explanation:
Answer:
Explanation:
Equivalent resistance is 1 / ((1/1) + (1/2) + (1/2) + (1/3)) = 3/7 Ω
I = V/R = 4(7/3) = 28/3 = 9.3 A
