Answer:
30 m/s
Step-by-step explanation:
Let's say the distance from the first car to the intersection is x, and the distance from the second car to the intersection is y.
The distance between the cars can be found with Pythagorean theorem:
d² = x² + y²
Taking derivative with respect to time:
2d dd/dt = 2x dx/dt + 2y dy/dt
d dd/dt = x dx/dt + y dy/dt
We know that x = 200, dx/dt = -25, y = 150, and dy/dt = -50/3.
To find dd/dt, we still need to find d.
d² = x² + y²
d² = (200)² + (150)²
d = 250
Plugging everything in:
250 dd/dt = (200) (-25) + (150) (-50/3)
dd/dt = -30
The cars are approaching each other at a rate of 30 m/s at that instant.
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Therefore, the value of n is 30.
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Hence verified.
Answer:
a) $0.97
b) $0.16
c) $24.30
Step-by-step explanation:
$0.09 per kilowatt hour = $0.09/kWh
6h/day 30 days = 180h
a) 60W*180h = 10800 Wh = 10.8kWh
10.8kWh * $0.09/kWh = $0.97
b) P = V*I
V = 120V
I = 80mA = 80/1000 = 0.08A
P = 120*0.08 = 9.6W
9.6W*180h = 1728 Wh = 1.728kWh
1.728kWh * $0.09/kWh = $0.16
c) 1500W*180h = 270000 Wh = 270kWh
270kWh * $0.09/kWh = $24.30
I think that 3 rolls is wrong and that 6 rolls is right. If you create a 15 by 15 square and draw two lines through the center that connect to the opposite corner, you'll be able to use the Pythagorean Theorem.
Perimeter: 15+15+15+15=60ft.
Length of Line from Corner to Corner:
(15)(15)+(15)(15)=C^2
225+225=C^2
450=C^2
21.2=C
21.2(2)= 42.4ft.
42.4ft.+60ft.= 102.4ft.
102.4ft. divided by 20ft. = 5.12 = <u>6 rolls</u>
Step-by-step explanation:
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