The answer is D: all electromagnetic waves can travel in a vacuum
Answer:
V=34.2 m/s
Explanation:
Given that
Height , h= 54 m
Horizontal distance , x = 35 m
Given that , the ball is thrown horizontally , therefore the initial vertical velocity will be zero.
In vertical direction :
We know that

Now by putting the values in the above equation we got


Assume 
Thus



We also know that



In horizontal direction :


Thus the resultant velocity


V=34.2 m/s
Therefore the velocity will be 34.2 m/s.
The speed of a car travelling over a hill that has a radius of curvature should not exceed a certain speed other it will topple. This speed is related to the radius of curvature and the gravitational acceleration as shown below:
V^2 = Rg, where V = maximum speed, R = Radius of curvature, g = gravitational acceleration.
Substituting;
V = Sqrt (Rg) = Sqrt (120*9.81) = 34.31 m/s
Answer:
a. I = 30 A
b. E = 1080000 J = 1080 KJ
c. ΔT = 12.86°C
d. Cost = $ 4.32
Explanation:
a.
The current in the coil is given by Ohm's Law:

where,
I = current = ?
V = Voltage = 120 V
R = Resistance = 4 Ω
Therefore,

<u>I = 30 A</u>
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b.
The energy can be calculated as:

<u>E = 1080000 J = 1080 KJ</u>
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c.
For the increase in the temperature of water:

where,
m = mass of water = 20 kg
C = specific heat of water = 4.2 KJ/kg.°C
Therefore,

<u>ΔT = 12.86°C</u>
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d.
First, we will calculate the total energy consumed:

Now, for the cost:

<u>Cost = $ 4.32</u>
I think it is acceleration