If you have fifty 15-ohm resistors all connected in parallel, their "effective" resistance is (15/50) = 0.3 ohms.
Current = (voltage) / (resistance)
Current = (115 V) / (0.3 ohm)
<em>Current = 383.3 Amperes</em>
This is an interesting question, with a VERRRRY interesting answer. The fuse or circuit breaker that feeds the outlet where these lights are plugged in is most likely rated 15 or 20 or 25 Amperes, and it trips immediately.
But let's say it doesn't ... let's say the juice just keeps on flowing.
Power = (voltage) x (current)
These lights use energy at the rate of (115V)x(383.3A) = 44,083 watts. This is roughly the same as the power used to run 22 toasters or 37 blow-dryers, all at the same time. AND ... the lights are going to produce almost as much <u>heat</u> as 22 toasters or 37 blow-dryers all running at the same time. The lights will probably burn the house down before long.
If electrical energy costs 20¢ per kilowatt-hour in this city, then running those lights for ONE HOUR is going to cost $8.82 !
All in all, it will be a good idea to unplug the Christmas tree lights when the family goes to bed.
Answer:
Time 10.0 s
Explanation:
Given:
H = 494.9 m
V = 27.6 m/s
g = 9.8 m/s²
___________
t - ?
The fall time is found from the formula:
H = g·t² / 2
t = √ (2·H / g) = √ (2·494.9 / 9.8 ) ≈ 10.0 s
Attention! An extra given is speed. Find the distance from the base of the rock to the point where the stone fell:
L = V·t = 27.6·10.0 = 276 m
Since there is a meeting of the cables at their midpoints, it is therefore understood that the force on them is the same but in the opposite direction, this to maintain the static balance between the two.
This can also be corroborated by applying the right hand rule for the force, at which depends of the magnetic field. The net force is zero because the cable segment to the left of the vertical cable feels an opposite force in the direction of the cable segment to the right.
Then the forces cancel.
Therefore the correct answer is C. Therefore the net force on each wire is zero
answer - d
set up equation
the velocity can be found through the change in kinetic energy
due to the conversation of energy, the change in kinetic energy is the same as the change in potential energy when the height is changed
ΔK =
ΔU = mgΔh
ΔK = ΔU
= mgΔh
= 2gΔh
v =
values
g = 9.8
Δh = 42 - 4.2 = 37.8 m
plug in values
v =
v =
v = 27.2
answer choice D