Columbia Invitational — Hovercraft

Hovercraft · Division C · Columbia Invitational · 2018

13 questions · 46 points · 50 min· 1 question from the original omitted

Identify the choice that best completes the statement or answers the question.

Multiple Choice

Question 1

1 pt

Explain the difference between a scalar and a vector quantity.

A. A scalar involves both magnitude and direction, a vector involves both magnitude and direction.B. A scalar involves only magnitude, a vector involves only direction.C. A scalar involves only magnitude, a vector involves both magnitude and direction.D. A scalar involves only direction, a vector involves only magnitude.

Question 2

1 pt

Which of the following is a vector quantity?

A. PressureB. ForceC. TemperatureD. Mass

Short Answer

PassageFor questions 3–4, 6

A hovercraft leaves the dock at 10 AM and travels due east at 60 km/h. After 20 min the craft turns due south and continues at the same speed for an additional 10 min.

Question 3

4 pts

At this point, what is the total distance traveled by the hovercraft?

Question 4

4 pts

What is the craft's displacement to the nearest 0.1 km?

Question 6

4 pts

What is the crafts average velocity to the nearest 1 km/h?

PassageFor questions 7–10

At this point the craft experiences a mechanical failure and launches an emergency flare.

Question 7

4 pts

For maximum visibility (greatest vertical height) the captain decides to launch the flare straight up. However before releasing the flare, the captain sees another vessel 5 km due south. At what angle (above horizontal) should he launch the flare to place the flare as close to the vessel as possible?

Question 8

4 pts

Assume a standard flare can reach an altitude of 300m when fired directly upward. If the captain chooses an angle of 50° above the horizontal, how many seconds (to the nearest 0.1 s) will it take for his flare to strike the water (neglect air resistance)

Question 9

4 pts

Given a 10 m/s wind from the south, what is the horizontal distance traveled by the flare to the nearest 0.1 meters?

Question 10

4 pts

Given the horizontal distance calculated above, did the captain increase the visibility of the flare by launching at an angle other than vertical? In other words: did launching at a lower angle allow more photons to reach the other vessel? (Assume the flare burns with a constant luminosity until it strikes the water)

Question 11

4 pts

A 100,000.0 kg spaceship must increase its velocity by 0.23 m/s in order to correctly reenter the earth's atmosphere. If the rockets thrusters are capable of ejecting spent fuel at 50000.0 m/s, calculate how much fuel (in kg) is required in order to accelerate the spaceship.

Question 12

4 pts

A 750 kg hovercraft is traveling at a constant speed while its fan generates a continual thrust of 1500 Newtons. What is the sum of all the drag forces on the craft.

Question 13

4 pts

The system shown consists of three fluids with densities of 800 kg/m^3, 1000 kg/m^3, and 13600 kg/m^3. Calculate P_A - P_0 to the nearest Pascal. (use g = 9.8m/s^2)

Question 14

4 pts

In the system shown water is expressed from a pressurized tank. Find v (velocity to the nearest 0.01 m/s) Given: P_1 = 3 x 10^5 Pa P_0 = 10^5 Pa ρ = 1000 kg/m^3 h = 0.25 m