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Brut [27]
3 years ago
7

The skateboarder has a mass of 100 kg. When traveling downward from E to D, he reaches a velocity of 11 m/s. Calculate his kinet

ic energy at D (explain work and include units please).
(KE= ½ mv2)

Physics
1 answer:
patriot [66]3 years ago
6 0

6050 J is the kinetic energy at D

<u>Explanation:</u>

In physics, the object's kinetic energy (K.E) defined as the energy it possesses during movement. It can be defined as the required work to accelerate a certain body weight in order to rest at a certain speed. When the body receives this energy as it speeds up (accelerates), it retains this energy unless speed varies. The equation is given as,

           K . E=\frac{1}{2} \times m \times v^{2}

Where,

m - mass of an object

v - velocity of the object

Here,

Given data:

m  = 100 kg

v = 11 m/s

By substituting the given values in the above equation, we get

            K . E=\frac{1}{2} \times 100 \times(11)^{2}=\frac{1}{2} \times 100 \times 121=\frac{12100}{2}=6050\ \mathrm{J}

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Answer:

The ratio is 9.95

Solution:

As per the question:

Amplitude, y_{m} = 8.4\ cm

Wavelength, \lambda = 5.3\ cm

Now,

To calculate the ratio of the maximum particle speed to the speed of the wave:

For the maximum speed of the particle:

v_{m} = y_{m}\times \omega

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\omega = 2\pi f = angular speed of the particle

Thus

v_{m} = 2\pi fy_{m}

Now,

The wave speed is given by:

v = f\lambda

Now,

The ratio is given by:

\frac{v_{m}}{v} = \frac{2\pi fy_{m}}{f\lambda}

\frac{v_{m}}{v} = \frac{2\pi \times 8.4}{5.3} = 9.95

8 0
3 years ago
The wavelength of light that has a frequency of 1.20 × 1013 s-1 is ________ m.
klio [65]
The relationship between frequency and wavelength for an electromagnetic wave is
c=f \lambda
where
f is the frequency
\lambda is the wavelength
c=3 \cdot 10^8 m/s is the speed of light.

For the light in our problem, the frequency is f=1.20 \cdot 10^{13} s^{-1}, so its wavelength is (re-arranging the previous formula)
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8 0
3 years ago
At a picnic, there is a contest in which hoses are used to shoot water at a beach ball from three different directions. As a res
hram777 [196]

Answer:

F₃ = 122.88 N

θ₃ = 20.63°

Explanation:

First we find the components of F₁:

For x-component:

F₁ₓ = F₁ Cos θ₁

F₁ₓ = (50 N) Cos 60°

F₁ₓ = 25 N

For y-component:

F₁y = F₁ Sin θ₁

F₁y = (50 N) Sin 60°

F₁y = 43.3 N

Now, for F₂. As, F₂ acts along x-axis. Therefore, its y-component will be zero and its x-xomponent will be equal to the magnitude of force itself:

F₂ₓ = F₂ = 90 N

F₂y = 0 N

Now, for the resultant force on ball to be zero, the sum of x-components of the forces and the sum of the y-component of the forces must also be equal to zero:

F₁ₓ + F₂ₓ + F₃ₓ = 0 N

25 N + 90 N + F₃ₓ = 0 N

F₃ₓ = - 115 N

for y-components:

F₁y + F₂y + F₃y = 0 N

43.3 N + 0 N + F₃y = 0 N

F₃y = - 43.3 N

Now, the magnitude of F₃ can be found as:

F₃ = √F₃ₓ² + F₃y²

F₃ = √[(- 115 N)² + (- 43.3 N)²]

<u>F₃ = 122.88 N</u>

and the direction is given as:

θ₃ = tan⁻¹(F₃y/F₃ₓ) = tan⁻¹(-43.3 N/-115 N)

<u>θ₃ = 20.63°</u>

7 0
2 years ago
A runner moves west with an initial velocity of 4 m/s. She accelerates 3 m/s2 for 30 seconds. The runner's final velocity is
Firlakuza [10]

Answer:

v = 94m/s

Explanation:

Using the first equation of motion

v = u + at

u = 4m/s , a = 3m/s² , t = 30s , v = ?

v = u + at

v = 4 + 3 × 30

v = 4 + 90

v = 94m/s

I hope this was helpful, please mark as brainliest

3 0
2 years ago
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There is no right or wrong answer, your teacher wants you to support your own answer with points. As long as the reasons make logical sense you are fine.

I think they both have valid points. Their replies are both true, but from a buyer's perspective who would you purchase services from? You would get different answers depending on who you ask.

If you choose to go old school, obviously you get an actual photo that can be stored physically. This means it is a memory that can be preserved, and it might feel more nostalgic being able to touch the photo.

On the other hand, a digitally stored photo can be altered (photoshop), but it is forever as long as the internet still exists. A physical photo would fade with time, which doesn't happen with a digital photo.

It is definitely easier to argue that digital photography has more advantages (they do, it is why nobody uses film anymore)

Points you can consider:

Can be transferred to the other side of the world instantly

Ability to make copies and print as many photos as you want

Can be stored on cloud/devices and be like that forever

Compare them with film photography to give a more solid response.

3 0
3 years ago
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