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Ad libitum [116K]
3 years ago
7

1. An object in free fall will have an initial velocity equal to zero when: a. It is thrown vertically down

Physics
1 answer:
Ne4ueva [31]3 years ago
6 0

Answer:

b. It is dropped

Explanation:

If the initial velocity is zero, the object move from rest. That happens if the object is dropped

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An engine flywheel initially rotates counterclockwise at 6.55 rotations/s. Then, during 20.9 s, its rotation rate changes to 2.1
11Alexandr11 [23.1K]

Answer:

The average angular acceleration is -2.628 rad/s²

Explanation:

Counterclockwise = positive

Clockwise = -negative

Given;

initial rotation of the flywheel, θ₁ = 6.55 rotation/s

final rotation of the flywheel, θ₂ = - 2.19 rotation/s

The average angular acceleration is given by;

\alpha = \frac{\delta \theta}{\delta t}\\\\ \alpha =\frac{\theta _2 - \theta_ 1}{t}\\\\ \alpha =\frac{-2.19 -6.55}{20.9} \\\\ \alpha =\frac{-8.74}{20.9}\\\\ \alpha = -0.4182 \ rotation / s^2\\\\ \alpha = \frac{-0.4182 \ rotation}{s^2}*\frac{2\pi \ radian}{rotation}\\\\ \alpha = -2.628 \ rad/s^2

Therefore, the average angular acceleration is -2.628 rad/s²

7 0
3 years ago
The battery charger for an mp3 player contains a step-down transformer with a turns ratio of 1:38, so that the voltage of 120 v
matrenka [14]
Transformer contains two coils: primary and secondary. They allow change of voltage to lower or higher value. In first case we have step-down and in second case we have step-up transformer.
Formula used for transformer is:\frac{N_{1} }{N_{2}} = \frac{V_{1}}{V_{2}}

Where:N1 = number of turns on primary coilN2 = number of turns on secondary coilV1 = voltage on primary coilV2 = voltage on secondary coil
In a step-down transformer primary coil has more turns than secondary coil. So the ratio 1:38 means that for each turn on secondary coil we have 38 turns on primary coil.
We can solve the equation for V2:V_{2} =  \frac{ V_{1}* N_{2}  }{ N_{1} }  \\  V_{2} =  \frac{ 120* x  }{ 38x} } \\ V_{2} = 3.16V

Secondary coil provides voltage of 3.16V.
7 0
3 years ago
Find the current passing through a circuit consisting of a battery and one resistor. The resistance has a retance of 2ohms and t
Bingel [31]

The current passing through a circuit consisting of a battery of 12 V and resistor of 2 ohms is 6 Ampere .

Explanation:

  • Assume the wires are ideal with zero resistance.  
  • The current passing through the circuit will be  

           I = V/R = 12/2 = 6.000 A.

5 0
3 years ago
a kickball is struck with a 15.2 m/s velocity at a 63.0 degree angle. it lands on a rooftop 2.40 s later. how high is the roof?​
Serhud [2]

Refer to the attachment

3 0
3 years ago
If we warm a volume of air, it expands. Does it then follow that if we expand a volume of air, it warms? Explain.
Ivahew [28]

Answer:

nope don't think so

Explanation:

the heat causes the molecules to move faster therefore expanding in watever it the air is in

3 0
3 years ago
Read 2 more answers
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