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3 years ago

3. A bird flying 4 m/s has 8 joules of kinetic energy. What is the mass of the bird?

Physics

1 answer:

lesya692 [45]3 years ago

3 0

Answer:

The mass of the bird is 1 [kg]

Explanation:

The kinetic energy is defined by the following equation:

$E_{k} =\frac{1}{2} *m*v^{2}\\$

where:

m= mass of the bird [kg]

v = velocity of the bird [m/s]

Ek = kinetic energy [J]

We need to clear the mass from the equation given.

$m=\frac{2*E_{k} }{v^{2}} \\m=\frac{2*8}{(4)^{2} } \\m=1 [kg]$

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3 years ago

A 50.-kilogram rock rolls off the edge of a cliff. if it is traveling at a speed of 24.2 m/s when it hits the ground, what is th

ElenaW [278]

The correct answer to the question is : 29.88 m.

EXPLANATION :

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The final velocity of the rock when it hits the ground v = 24 .2 m/s.

Let the height of the cliff is h.

The potential energy gained by the rock at the top of the cliff = mgh.

Here, g is known as acceleration due to gravity, and g = $9.8\ m/s^2$

When the rock rolls off the edge of the cliff, the potential energy is converted into kinetic energy.

When the rock hits the ground, whole of its potential energy is converted into its kinetic energy.

The kinetic energy of the rock when it touches the ground is given as -

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From above we know that -

Kinetic energy at the bottom of the cliff = potential energy at a height h

$\frac{1}{2}mv^2=\ mgh$

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Twisting the peg only changed the string's tension; the length
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-- If you twisted the peg in the direction that made the string slightly
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-- If you twisted the peg in the direction that made the string slightly
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Answer:

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