A major-league pitcher throws a baseball toward home plate. The ball rotates at 1560 rpm, and it travels the 18.5 meters to the
1 answer:
Answer:
no of revolutions = 56.62 rev
Explanation:
given data
rotates = 1560 rpm
travels distance = 18.5 meters
speed = 40.2 m/s
solution
first we convert here rev/min to rev/sec
rotates = 1560 rpm = 1560 × 0.0167 = 26.052 rev/sec
we get here no of revolutions that is
no of revolutions = spin rotate ÷ time ..........1
here time = distance ÷ speed
time = 18.5 ÷ 40.2
time = 0.4601 s
put value in equation 1 we get
no of revolutions =
no of revolutions = 56.62 rev
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Answer:
The average rate of energy transfer to the cooker is 1.80 kW.
Explanation:
Given that,
Pressure of boiled water = 300 kPa
Mass of water = 3 kg
Time = 30 min
Dryness friction of water = 0.5
Suppose, what is the average rate of energy transfer to the cooker?
We know that,
The specific enthalpy of evaporate at 300 kPa pressure
We need to calculate the enthalpy of water at initial state
We need to calculate the enthalpy of water at final state
Using formula of enthalpy
Put the value into the formula
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Using formula of rate of energy
Put the value into the formula
Hence, The average rate of energy transfer to the cooker is 1.80 kW.
<h2>Complete Question:</h2>
You are on an aluminum ladder that is standing on the ground, trying to fix an electrical connection with a metal screwdriver having a metal handle. Your body is wet because you are sweating from the exertion; therefore, it has a resistance of 1.60 kΩ .
(a) If you accidentally touch the "hot" wire connected to the 120 V line, how much current will pass through your body?
(b) How much electrical power is delivered to your body?
<h2>Answer:</h2>(a) 0.075A
(b) 9W
<h2>Explanation:</h2>The voltage (V) passing across or supplied to a body is directly proportional to the current (I) flowing through the body as stated by Ohm's law. i.e
V ∝ I
=> V = I x R ----------------------(i)
Where;
R = constant of proportionality called resistance of the body
(a) As stated in the question;
The body is wet and thus will conduct electricity and has the following;
V = voltage supplied = 120V
R = resistance of the wet body = 1.60kΩ = 1.6 x 1000Ω = 1600Ω
Substitute these values into equation(i) as follows;
120 = I x 1600
Solve for I;
I =
I = 0.075A
Therefore the amount of current that will pass through your body is 0.075A
(b) Electrical power(P), which is commonly measured in Watts(W), delivered to a body is the product of the current(I) and voltage (V) supplied to the body. i.e
P = I x V ---------------------(ii)
Where;
I = 0.075A [as calculated above]
V = 120V [given in the question]
Substitute these values into equation (ii) as follows;
P = 0.075 x 120
P = 9W
Therefore, the electric power delivered to your body is 9W
Answer:
The tension in the string is quadrupled i.e. increased by a factor of 4.
Explanation:
The tension in the string is the centripetal force. This force is given by
m is the mass, v is the velocity and r is the radius.
It follows that , provided m and r are constant.
When v is doubled, the new force, , is
Hence, the tension in the string is quadrupled.