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2 years ago

A 4kg bird has 8 joules of kinetic energy, how fast is it flying?

Physics

2 answers:

Igoryamba2 years ago

7 0

I believe the answer is 2m/s

JulijaS [17]2 years ago

6 0

Answer:

The bird is flying at a velocity of $v=2\frac{m}{s}$

Explanation:

You should use the equation for the kinetic energy, that is:

$K_{E}=\frac{1}{2}mv^{2}$

where $K_{E}$ is the kinetic energy, m is the mass of the bird and v is its velocity.

Solving for v:

$mv^{2}=2K_{E}$

$v^{2}=\frac{2K_{E}}{m}$

$v=\sqrt{\frac{2K_{E}}{m}}$

And replacing the values given in the problem you have:

$v=\sqrt{\frac{2*8J}{4kg}}$

$v=\sqrt{\frac{16J}{4kg}}$

$v=\sqrt{4\frac{m^{2}}{s^{2}}}$

$v=2\frac{m}{s}$

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An 80.0-kg object is falling and experiences a drag force due to air resistance. The magnitude of this drag force depends on its

FromTheMoon [43]

Answer:

The terminal speed of this object is 12.6 m/s

Explanation:

It is given that,

Mass of the object, m = 80 kg

The magnitude of drag force is,

$F_{drag}=12v+4v^2$

The terminal speed of an object is attained when the gravitational force is balanced by the gravitational force.

$F_{drag}=mg$

$12v+4v^2=80\times 9.8$

$4v^2+12v=784$

On solving the above quadratic equation, we get two values of v as :

v = 12.58 m/s

v = -15.58 m/s (not possible)

So, the terminal speed of this object is 12.6 m/s. Hence, this is the required solution.

6 0

1 year ago

A hockey stick strikes a hockey puck of mass 0.17 kg. If the force exterted on the hockey puck is 35.0 N and there is a force of

GREYUIT [131]

Answer:

$a=190\ m/s^2$

Explanation:

Mass of a hockey puck, m = 0.17 kg

Force exerted by the hockey puck, F' = 35 N

The force of friction, f = 2.7 N

We need to find the acceleration of the hockey puck.

Net force, F=F'-f

F=35-2.7

F=32.3 N

Now, using second law of motion,

F = ma

a is the acceleration of the hockey puck

$a=\dfrac{F}{m}\\\\a=\dfrac{32.3}{0.17}\\\\a=190\ m/s^2$

So, the acceleration of the hockey puck is $190\ m/s^2$ .

5 0

2 years ago

If a 1000-pound capsule weighs only 165 pounds on the moon, how much work is done in propelling this capsule out of the moon's g

yulyashka [42]

Answer:

178200 g mile pounds

Explanation:

Work= Force * Distance= Fh

F=ma=mg where m is mass and g is acceleration due to gravity

Work= 165 pounds *g* 1080 m= 178200 g mile pounds

5 0

2 years ago

Which of these discoveries contradict components of Dalton’s atomic theory? Check all of the boxes that apply. Atoms contain sma

EastWind [94]

Explanation:

According to Dalton's atomic theory, all the atoms are individual, all the atoms of the same element are identical in properties and mass, the compound is formed from two or more kinds of the atoms, all the matter is made up of small atoms and the chemical reaction is a rearrangement of the atoms.

The discoveries which contradicts the components of Dalton's atomic theory from the given discoveries are:

Nuclear reactions can change an atom of one element into an atom of another element.

Atoms of a given element can have different numbers of neutrons.

Atoms contain smaller particles: protons, neutrons, and electrons.

4 0

2 years ago

Read 2 more answers

A certain humidifier operates by raising water to the boiling point and then evaporating it. Every minute 30 g of water at 20◦ C

Sveta_85 [38]

Answer:

The value of total energy needed per minute for the humidifier = 77.78 KJ

Explanation:

Total energy per minute the humidifier required = Energy required to heat water to boiling point) + Energy required to convert liquid water into vapor at the boiling point) ----- (1)

Specific heat of water = 4190 $\frac{J}{kg k}$