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seraphim [82]
3 years ago
8

A railroad car moving at a speed of 3.49 m/s overtakes, collides, and couples with two coupled railroad cars moving in the same

direction at 1.28 m/s. All cars have a mass of mass 1.08 105 kg. Determine the following.
(a) speed of the three coupled cars after the collision (Give your answer to at least 2 decimal places.)(b) kinetic energy lost in the collision
Physics
1 answer:
Mandarinka [93]3 years ago
7 0

Answer:

Explanation:

Using conservation law of momentum

let m₁ = mass of the railroad, initial u₁ = 3.49 m/s

let m₂ = mass of one of the coupled car,  u₂= 1.28m/s

let m₃ = mass of the second car u₃ = 1.28 m/s

m₁u₁ + m₂u₂ + m₃u₃ = v ( m₁ + m₂ + m₃)

since the masses are the same

m₁ = m₂ = m₃

m ( 3.49 + 1.28 + 1.28) = 3m v

6.05 m = 3 mv

v = 6.05 m / 3m = 2.0167 m/s

b) kinetic energy lost = energy before collision - energy after collision

= (0.5m₁u₁² + 0.5 ( m₁+m₂) u₂² - 0.5 ( m₁ + m₂ + m₃) v

= (6.58365 + 1.7712) - 6.5951 = 1.76J  

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masha68 [24]

Answer: A wavelength is how long ONE wave is. First divide the distance of the whole diagram by the number of waves. you will get 2m. This is the answer.

6 0
3 years ago
Two stretched copper wires both experience the same stress. The first wire has a radius of 3.9×10-3 m and is subject to a stretc
maw [93]

The stretching force acting on the second wire, given the data is 588 N

<h3>Data obtained from the question</h3>
  • Radius of fist wire (r₁) = 3.9×10⁻³ m
  • Force of first wire (F₁) = 450 N
  • Radius of second wire (r₂) = 5.1×10⁻³ m
  • Force of second wire (F₂) =?

<h3>How to determine the force of the second wire</h3>

F₁ / r₁ = F₂ / r₂

450 / 3.9×10⁻³ = F₂ / 5.1×10⁻³

cross multiply

3.9×10⁻³ × F₂ = 450 × 5.1×10⁻³

Divide both side by 3.9×10⁻³

F₂ = (450 × 5.1×10⁻³) / 3.9×10⁻³

F₂ = 588 N

Learn more about spring constant:

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7 0
2 years ago
An infinite long straight wire is uniformly charged, the charge density is a. Use Coulomb's law to calculate the electric field
bixtya [17]

Answer:

\vec{E} = \frac{a}{2\pi \epsilon_0 R}\^R

Explanation:

Since the wire is infinitely long, we will use Gauss' Law:

\int\vec{E}d\vec{a} = \frac{Q_{enc}}{\epsilon_0}

We will draw an imaginary cylindrical surface with height h around the wire. The electric flux through the imaginary surface will be equal to the net charge inside the surface.

In that case, the net charge inside the imaginary surface will be the portion of wire with height h. Then the charge of that portion will be equal to

Q_{enc} = ah

The left-hand side of the Gauss' Law is the flux through the imaginary surface. Since we choose our surface as a cylinder, of which we know the area, we do not have to take the surface integral.

\int\vec{E}d\vec{a} = E2\pi R h

where R is the radius of the imaginary cylinder.

Finally, Gauss' Law gives

E2\pi Rh = \frac{ah}{\epsilon_0}\\E = \frac{a}{2\pi \epsilon_0 R}

The vector expression is

\vec{E} = \frac{a}{2\pi \epsilon_0 R}\^R

As you can see, the electric field is independent from the height h, since that is merely an imaginary cylinder to apply Gauss' Law. In the end, what matters is the charge density of the wire and the distance from the wire.

4 0
4 years ago
The work done on an elevator that has a mass of 1000kg and lifted 4m in 10 seconds is how many joules.
GaryK [48]

Answer:

39,200 Joules

3920 watts

Explanation:

5 0
4 years ago
Two fish swimming in a river have the following equations of motion:
IRINA_888 [86]

Answer:

The second fish, X2, is moving faster than the first fish, X1

Explanation:

The given parameters for the equation of motion of the fishes are;

X1 = -6.4 m + (-1.2 m/s)×t

X2 = 1.3 m + (-2.7 m/s)×t

The given equation are straight line equations in the slope and intercept form, where the slope is the speed and in m/s and the intercept is the starting point of swimming of the fishes

For the first fish, the intercept = -6.4 m, the slope = the  speed = -1.2 m/s

For the second fish, the intercept = 1.3 m, the slope = the  speed = -2.7 m/s

Whereby the fishes are swimming in the opposite direction of the measurement of length, we have;

The magnitude of the speed of the second fish \left | -2.7 \ m/s \right | = 2.7 \ m/s, is larger than the magnitude of the speed of the first fish \left | -1.2 \ m/s \right | = 1.2 \ m/s

Therefore, the second fish, X2, is moving faster than the first fish, X1.

8 0
3 years ago
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