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3 years ago

A ball is thrown into the air with 100 J of kinetic energy, which is transformed to gravitational potential energy

Physics

1 answer:

natka813 [3]3 years ago

8 0

Answer:

Option A

Air resistance

Explanation:

Despite the law of conservation of energy stating that energy can neither be created nor destroyed but can only be transformed from one state to the other, the process of transformation is not 100% efficient since some energy losses occur due to friction and air resistance. Therefore, when the final energy is slightly less than the original dor this case, it's due to energy loss due to air resistance.

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How can acceleration be changed without changing speed?

katrin [286]

Since velocity is a speed and a direction, there are only two ways for you to accelerate: change your speed or change your direction—or change both. If you're not changing your speed and you're not changing your direction, then you simply cannot be accelerating—no matter how fast you're going.

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3 years ago

A 65.0 kg diver is 4.90 m above the water, falling at speed of 6.40 m/s. Calculate her kinetic energy as she hits the water. (Ne

mojhsa [17]

Answer:

4452.5 J.

Explanation:

The diver have both kinetic and potential energy.

Ek = 1/2mv² ................. Equation 1

Where Ek = Kinetic Energy of the diver, m = mass of the diver, v = velocity of the diver.

Given: m = 65 kg, v = 6.4 m/s.

Substitute into equation 1

Ek = 1/2(65)(6.4²)

Ek = 1331.2 J.

Also,

Ep = mgh ............................ Equation 2

Where Ep = Potential energy of the diver when its above the water, h = height of the diver above the water, g = acceleration due to gravity.

Given: m = 65 kg, h = 4.9 m, g = 9.8 m/s²

Substitute into equation 2.

Ep = 65(4.9)(9.8)

Ep = 3121.3 J.

Note: When she hits the water, the potential energy is converted to kinetic energy.

E = Ek+Ep

Where E = Kinetic energy of the diver when she hits the water.

E = 1331.2+3121.3

E = 4452.5 J.

3 0

3 years ago

How much energy does a 100-W light bulb use in 10 s?

telo118 [61]

Answer:c

Explanation:

8 0

4 years ago

20. In a parallel RL circuit, 10 mA flows through the resistor and 4 mA flows through the inductor. What phase angle separates v

stellarik [79]

Answer:

Option D: 21.8 degrees

Explanation:

In a parallel RL circuit, the current in the resistor R and that in the inductor L are separated among themselves 90 degrees as illustrated in the attached image. In the image the current in the resistor is represented in orange, that of the inductor in blue, and the total current (vector addition of the previous two) is represented in red, forming a certain angle (theta) with respect to the current in the resistor. The output voltage is the same as the input voltage as measured over the resistor R.

Therefore, the phase angle that separated output voltage and total current can be obtained using the fact that tan(phase angle) = $\frac{I_l}{I_R} = \frac{x}{y} \frac{4}{10}$ , therefore the angle is the arctangent of 4/10:

$arctang(\frac{4}{10} )= 21.801$ degrees.

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4 years ago

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A device used to measure a mass of an object is called

OLga [1]

Answer:

I am explain you in image

8 0

3 years ago