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gtnhenbr [62]
3 years ago
15

A car’s engine provides a forward force of 500 N. It is opposed by a resistive force of 200 N. The car accelerates forwards for

20 m. How much work is done by each force? By how much does the car’s energy increase?​
Physics
1 answer:
wariber [46]3 years ago
5 0

Answer:

Explanation:

W = Fd

Engine 500(20) = 10000 J

friction 200(-20) = -4000 J

Energy increase is 10000 - 4000 = 6000 J

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(15pts) A hungry 12.0 kg fish is coasting from west to east at 75 cm/s when it suddenly swallows a 1 kg fish swimming towards it
faust18 [17]

Answer:

The speed of the big fish after swallowing the small fish is 0.38 m/s.

Explanation:

Consider west to east direction as positive and the opposite direction as negative.

Given:

Mass of big fish (m₁) = 12.0 kg

Initial velocity of big fish (u₁) = 75 cm/s = 0.75 m/s

Mass of small fish (m₂) = 1 kg

Initial velocity of small fish (u₂) = -4 m/s (Direction is opposite to u₁)

After swallowing the small fish, both the fishes move together with same velocity. Let the velocity be 'v'.

So, as there are no effects of drag or any other forces, the given scenario can be considered as a case of inelastic collision where the objects move together with same velocity after collision.

The momentum is conserved in inelastic collision. Therefore,

Initial momentum of the fishes = Final momentum of the fishes

m_1u_1+m_2u_2=(m_1+m_2)v\\\\v=\dfrac{m_1u_1+m_2u_2}{m_1+m_2}

Now, plug in the given values and solve for 'v'. This gives,

v=\frac{12.0\times 0.75+1\times (-4)}{12.0+1}\\\\v=\frac{9-4}{13}\\\\v=\frac{5}{13}=0.38\ m/s

Therefore, the speed of the big fish after swallowing the small fish is 0.38 m/s

3 0
3 years ago
Explain why nuclear fission and nuclear fusion release large amounts of energy
levacccp [35]

Answer:

Because of the formula E=mc^2

Explanation:

In this problem we are describing two different processes:

  • Nuclear fission occurs when a heavy, unstable nucleus breaks apart into two or more lighter nuclei
  • Nuclear fusion occurs when two (or more) light nuclei fuse together producing a heavier nucleus

In both cases, the total mass of the final products is smaller than the total mass of the initial nuclei.

According to Einsten's formula, this mass difference has been converted into energy, as follows:

E=\Delta mc^2

where:

E is the energy released in the reaction

\Delta m is the mass defect, the difference between the final total mass and the initial total mass

c=3.0 \cdot 10^8 m/s is the speed of light

From the formula, we see that the factor c^2 is a very large number, therefore even if the mass defect \Delta m is very small, nuclear fusion and nuclear fission release huge amounts of energy.

8 0
3 years ago
What will be the final temperature if a 4.00 g silver ring at 41.0◦C if it gives off 18.0 J of heat to the surroundings? The spe
Eduardwww [97]

Answer:

Final temperature, T_f=21.85^{\circ}

Explanation:

Given that,

Mass of silver ring, m = 4 g

Initial temperature, T_i=41^{\circ}C

Heat released, Q = -18 J (as heat is released)

Specific heat capacity of silver, c=0.235\ J/g\ C

To find,

Final temperature

Solution,

The expression for the specific heat is given by :

Q=mc\Delta T

Q=mc(T_f-T_i)

T_f=\dfrac{-Q}{mc}+T_i

T_f=\dfrac{-18}{4\times 0.235}+41

T_f=21.85^{\circ}

So, the final temperature of silver is 21.85 degrees Celsius.

5 0
3 years ago
The statement “Heavy objects fall faster than light objects” is an example of a(n) _______.
vazorg [7]
D. Theory is the answer
7 0
3 years ago
Calculate the change in the energy of an electron that moves from the n = 3 level to the n = 2 level. What type of light is emit
marissa [1.9K]

Answer:

Red light

Explanation:

The energy emitted during an electron transition in an atom of hydrogen is given by

E=E_0 (\frac{1}{n_2^2}-\frac{1}{n_1^2})

where

E_0 = 13.6 eV is the energy of the lowest level

n1 and n2 are the numbers corresponding to the two levels

Here we have

n1 = 3

n2 = 2

So the energy of the emitted photon is

E=(13.6) (\frac{1}{2^2}-\frac{1}{3^2})=1.9 eV

Converting into Joules,

E=(1.9 eV)(1.6\cdot 10^{-19} J/eV)=3.0\cdot 10^{-19} J

And now we can find the wavelength of the emitted photon by using the equation

E=\frac{hc}{\lambda}

where h is the Planck constant and c is the speed of light. Solving for \lambda,

\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34})(3\cdot 10^8)}{3.0\cdot 10^{-19}}=6.63\cdot 10^{-7} m = 663 nm

And this wavelength corresponds to red light.

5 0
3 years ago
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