Answer:
11.625
Explanation:
L = length of the ladder = 16 ft
= rate at which top of ladder slides down = - 3 ft/s
= rate at which bottom of ladder slides
y = distance of the top of ladder from the ground
x = distance of bottom of ladder from wall = 4 ft
Using Pythagorean theorem
L² = x² + y²
16² = 4² + y²
y = 15.5 ft
Also using Pythagorean theorem
L² = x² + y²
Taking derivative both side relative to "t"
= 11.625 ft/s
A. 0.77 A
Using the relationship:
where P is the power, V is the voltage, and R the resistance, we can find the resistance of each bulb.
For the first light bulb, P = 60 W and V = 120 V, so the resistance is
For the second light bulb, P = 200 W and V = 120 V, so the resistance is
The two light bulbs are connected in series, so their equivalent resistance is
The two light bulbs are connected to a voltage of
V = 240 V
So we can find the current through the two bulbs by using Ohm's law:
B. 142.3 W
The power dissipated in the first bulb is given by:
where
I = 0.77 A is the current
is the resistance of the bulb
Substituting numbers, we get
C. 42.7 W
The power dissipated in the second bulb is given by:
where
I = 0.77 A is the current
is the resistance of the bulb
Substituting numbers, we get
D. The 60-W bulb burns out very quickly
The power dissipated by the resistance of each light bulb is equal to:
where
E is the amount of energy dissipated
t is the time interval
From part B and C we see that the 60 W bulb dissipates more power (142.3 W) than the 200-W bulb (42.7 W). This means that the first bulb dissipates energy faster than the second bulb, so it also burns out faster.