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3 years ago

A dog running at a speed of 12 m/s has 1,080 J of kinetic energy. What is the mass of the dog

Physics

1 answer:

Gnom [1K]3 years ago

5 0

Answer:

The mass of the dog is 15 kg

Explanation:

We use the formula for the kinetic energy of the dog:

$KE=\frac{1}{2} m\,v^2$

Then, in our case:

$KE=\frac{1}{2} m\,v^2\\1080 \,=\,\frac{1}{2} m\,(12)^2\\m = \frac{2*1080}{144} \\m=15 \,\,kg$

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Which describes the greenhouse effect? 1. Earth continues to get warmer over time because it is slowly moving closer to the sun.

Alekssandra [29.7K]

Answer: The green house effect is best described by option 4 (Energy given off by earth is reflected off of earth's atmosphere back down to the surface).

Explanation:

The green house effect can be described as the energy given off by earth is reflected off of earth's atmosphere back down to the surface.

When energy from the sun passes through the atmosphere, some are absorbed which keeps the earth surface warm. While the rest is reflected back largely by cloud.

The energy which is emitted from the earth surface is called the infrared radiation. Some of the infrared radiation passess through the atmosphere but most is absorbed and re- emitted in all directions by the greenhouse gas molecules and clouds. This effect warms the earth surface and the lower atmosphere. Therefore this statement (Energy given off by earth is reflected off of earth's atmosphere back down to the surface) is correct about greenhouse effect.

For the greenhouse effect to occur, greenhouse gas molecules are mostly needed. Examples of these gases include:

--> Carbon dioxide (CO2),

--> Water vapor (H2O), and

--> Methane (CH4)

Over the years, the excessive human activities has lead to increase in the greenhouse gas molecules which has negatively affected the greenhouse effects.

6 0

3 years ago

If a small sports car collides head-on with a massive truck, which vehicle experiences the greater impact force? Which vehicle e

garri49 [273]

Answer:

Small sports car.

Explanation:

Lets take

mass of the small car = m

mass of the truck = M

As we know that when car collide with the massive truck then due to change in the moment of the car both car as well as truck will feel force.We also know that from Third law of Newton's ,it states that every action have it reaction with same magnitude but in the opposite direction.

Therefore

F = m a

a=Acceleration of the car

$a=\dfrac{F}{m}$

F= M a'

a'=Acceleration of the massive truck

$a'=\dfrac{F}{M}$

Here given that M > m that is why a > a'

Therefore car will experiences more acceleration.

5 0

3 years ago

Calculate the current flowing if a charge of 36 kilocoulombs flows in 1 hour.

kupik [55]

Answer:

2hrs and some mins

Explanation:

bc 2×36= 17 =)

3 0

3 years ago

A train travels 70 kilometers in 1 hours, and then 63 kilometers in 2 hours. What is its average speed?

lozanna [386]

The answer is: " 44 $\frac{1}{3}$ km " ;
or; write as: " 44.333 km " .
___________________________________________________________
Explanation:
___________________________________________________________
(70 km + 63 km) ÷ (2 + 1 ) = 133 km ÷ 3 = " 44 $\frac{1}{3}$ km " ;
or; write as: " 44.333 km " .
___________________________________________________________

3 0

3 years ago

"Which of the following statements about electrons is not true?

gogolik [260]

Answer:

B) Within an atom, an electron can have only particular energies.

Explanation:

As we know that electrons have energy but apart from electrons we know that protons and neutrons inside the nucleus of atom will also have energy in them.

rest all the statements are true as we have

A) Electrons orbit the nucleus rather like planets orbiting the Sun.

TRUE, because electrons can move in stationary orbit around the nucleus

C) Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels.

Difference amount of energy is lost or absorbed by the electron in form of photons

D) An electron has a negative electrical charge.

Charge of an electron is given as $-1.6 \times 10^{-19} C$

E) Electrons have very little mass compared to protons or neutrons

Mass of an electron is given as

$m_e = 9.11 \times 10^{-31} kg$

mass of proton or neutron

$m_p = 1.67 \times 10^{-27} kg$

7 0

3 years ago