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A ship with a mass of 20,000 accelerates from 14 knots to 17 knots over a period of 30 minutes. If its main engine does 3.00 X 108 of work on the ship, how far did the ship reach?

2 Answers

4 votes

Answer:

the ship traveled approximately 1.82 kilometers during its acceleration from 14 knots to 17 knots.

Step-by-step explanation:

To determine the distance the ship traveled, we can use the work-energy principle, which states that the work done on an object is equal to the change in its kinetic energy. The kinetic energy (KE) of an object with mass (m) and velocity (v) can be calculated using the following formula:

\[KE = \frac{1}{2}mv^2\]

The change in kinetic energy (ΔKE) is equal to the work done (W) on the object:

\[ΔKE = W\]

Given that the ship's mass (m) is 20,000 kg and its initial velocity (u) is 14 knots, and final velocity (v) is 17 knots, we need to convert the velocities to meters per second (m/s) because the mass is given in kilograms.

1 knot is approximately equal to 0.514444 m/s. So, we have:

Initial velocity (u) = 14 knots = 14 * 0.514444 m/s = 7.21 m/s

Final velocity (v) = 17 knots = 17 * 0.514444 m/s = 8.74 m/s

Now, we can calculate the initial kinetic energy (KE1) and final kinetic energy (KE2) of the ship:

\[KE1 = \frac{1}{2} \times 20,000 \, \text{kg} \times (7.21 \, \text{m/s})^2\]

\[KE2 = \frac{1}{2} \times 20,000 \, \text{kg} \times (8.74 \, \text{m/s})^2\]

The change in kinetic energy (ΔKE) is given by:

\[ΔKE = KE2 - KE1\]

Now, since ΔKE is equal to the work done on the ship (W), we have:

\[W = ΔKE = KE2 - KE1\]

Substitute the values and calculate ΔKE:

\[W = \left[\frac{1}{2} \times 20,000 \, \text{kg} \times (8.74 \, \text{m/s})^2\right] - \left[\frac{1/2}{2} \times 20,000 \, \text{kg} \times (7.21 \, \text{m/s})^2\]

Now, calculate ΔKE:

\[ΔKE = W = \left[\frac{1}{2} \times 20,000 \, \text{kg} \times (8.74 \, \text{m/s})^2\right] - \left[\frac{1}{2} \times 20,000 \, \text{kg} \times (7.21 \, \text{m/s})^2\]

\[ΔKE ≈ 899,346 \, \text{Joules}\]

The work done on the ship is approximately 899,346 Joules.

Now, we can use the work-energy principle to find the distance (d) the ship traveled. The work done is equal to the change in kinetic energy:

\[W = ΔKE = \frac{1}{2}mv^2 - \frac{1}{2}mu^2\]

We already have the values for W, m, u, and v. Rearrange the equation to solve for d:

\[d = \frac{W}{\frac{1}{2}mv^2 - \frac{1}{2}mu^2}\]

Now, plug in the values:

\[d = \frac{899,346 \, \text{J}}{\frac{1}{2} \times 20,000 \, \text{kg} \times (8.74 \, \text{m/s})^2 - \frac{1}{2} \times 20,000 \, \text{kg} \times (7.21 \, \text{m/s})^2}\]

Calculate the value of d:

\[d ≈ \frac{899,346 \, \text{J}}{0.5 \times 20,000 \, \text{kg} \times (76.5156 \, \text{m^2/s^2}) - 0.5 \times 20,000 \, \text{kg} \times (51.8841 \, \text{m^2/s^2})}\]

\[d ≈ \frac{899,346 \, \text{J}}{1530.312 - 1037.682}\]

\[d ≈ \frac{899,346 \, \text{J}}{492.63}\]

\[d ≈ 1821.35 \, \text{meters} \, \text{or} \, 1.82 \, \text{kilometers}\]

User Nolan Shang
by
8.8k points
4 votes

Answer:

the ship reached a distance of 150,000 knots.

Step-by-step explanation:

To calculate the distance the ship reached, we can use the formula:

Work = Force × Distance

In this case, the work done on the ship by its main engine is given as 3.00 × 10^8. We need to find the distance the ship reached.

To find the force, we can use the equation:

Force = Mass × Acceleration

Given that the ship has a mass of 20,000, we need to find the acceleration. We can use the formula:

Acceleration = (Final Velocity - Initial Velocity) ÷ Time

The initial velocity is 14 knots, the final velocity is 17 knots, and the time is given as 30 minutes.

Let's calculate the acceleration first:

Acceleration = (17 knots - 14 knots) ÷ 30 minutes

Acceleration = 3 knots ÷ 30 minutes

Acceleration = 0.1 knots per minute

Now, let's calculate the force:

Force = 20,000 × 0.1 knots per minute

Force = 2,000 knots per minute

Finally, we can find the distance using the formula:

Distance = Work ÷ Force

Distance = 3.00 × 10^8 ÷ 2,000 knots per minute

Distance = 1.50 × 10^5 knots

Therefore, the ship reached a distance of 150,000 knots.

User Leo Landau
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8.1k points