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3 years ago

13

Car headlights have both low beams and high beams. The high beams may be necessary when it is very dark outside. If the power fo

r the high beam is 60.0 watts and the current is 5.0 amps, how much voltage is required?
A.
65 volts
B.
0.088 volts
C.
12 volts
D.
55 volts

1 answer:

blsea [12.9K]3 years ago

6 0

Answer:

Voltage, V = 12 V.

Explanation :

It is given that,

The power for the high beam is, P = 60.0 watts

Current flowing, I = 5 A

Car headlights have both low beams and high beams. The high beams may be necessary when it is very dark outside.

So, the voltage required for the high beam is 12 V.

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where m = 58.0 kg is the mass of the projectile and $v=140 m/s$ is the initial speed. Substituting,

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We need to calculate the total mechanical energy of the projectile when it reaches its maximum height of y=336 m, where it is travelling at a speed of v=99.2 m/s.

The kinetic energy is

$K=\frac{1}{2}(58 kg)(99.2 m/s)^2=2.85\cdot 10^5 J$

while the potential energy is

$U=(58.0 kg)(9.8 m/s^2)(336 m)=1.91\cdot 10^5 J$

So, the mechanical energy is

$E=K+U=2.85\cdot 10^5 J+1.91 \cdot 10^5 J=4.76\cdot 10^5 J$

And the work done by friction is equal to the difference between the initial mechanical energy of the projectile, and the new mechanical energy:

$W=E_f-E_i=4.76\cdot 10^5 J-6.43\cdot 10^5 J=-1.67 \cdot 10^5 J$

And the work is negative because air friction is opposite to the direction of motion of the projectile.

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E = K

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