Hovercraft B/C

Test your knowledge of various Science Olympiad events.
User avatar
Justin72835
Member
Member
Posts: 175
Joined: June 25th, 2017, 7:06 am
Division: Grad
State: TX

Re: Hovercraft B/C

Postby Justin72835 » March 12th, 2018, 6:01 pm

What was the original formulation of Newton's Second Law that takes into account changes in mass?


Interestingly, Newton was referring to momentum when formulating this law and not force :D
Yep, your turn!
A large cylindrical tank with height 10 meters and radius 2.5 meters is filled up entirely with water. A circular hole with a radius of 10 cm is punctured underneath the tank. Given that the top of the tank is open to the atmosphere, how long will it take for the entire volume of water to flow out of the tank (assuming no change in flow rate due to changing height?
Last edited by Justin72835 on March 12th, 2018, 8:44 pm, edited 1 time in total.
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."


University of Texas at Austin '23
Seven Lakes High School '19

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Hovercraft B/C

Postby UTF-8 U+6211 U+662F » March 12th, 2018, 6:20 pm



Interestingly, Newton was referring to momentum when formulating this law and not force :D
Yep, your turn!
A large cylindrical tank with height 10 meters and radius 2.5 meters is filled up entirely with water. A circular hole with a radius of 10 cm is punctured underneath the tank. Given that the top of the tank is open to the atmosphere, how long will it take for the entire volume of water to flow out of the tank?





User avatar
Justin72835
Member
Member
Posts: 175
Joined: June 25th, 2017, 7:06 am
Division: Grad
State: TX

Re: Hovercraft B/C

Postby Justin72835 » March 12th, 2018, 8:49 pm

Yep, your turn!
A large cylindrical tank with height 10 meters and radius 2.5 meters is filled up entirely with water. A circular hole with a radius of 10 cm is punctured underneath the tank. Given that the top of the tank is open to the atmosphere, how long will it take for the entire volume of water to flow out of the tank?




I got [b]446 seconds[/b], which is basically half your answer. With that said, I think you made a mistake in your second line. Since you're multiplying both sides by two, the expression underneath the square root is g(20m) instead of g(5m). 

All your other work is correct though, so nice job! You can do the next one!
"The fault, dear Brutus, is not in our stars,
But in ourselves, that we are underlings."


University of Texas at Austin '23
Seven Lakes High School '19

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Hovercraft B/C

Postby UTF-8 U+6211 U+662F » March 13th, 2018, 6:08 pm

Oh whoops, haha.
Find the final speed of a 100 kg roller coaster car that has dropped 50 m (from rest), gone back up 30 m, dropped 60 m, gone back up 30 m, and then at that level been pushed for 5 seconds with a force of 50 Newtons.

MattChina
Member
Member
Posts: 224
Joined: February 12th, 2017, 8:06 am
Division: B
State: NY
Location: somewhere over the rainbow

Re: Hovercraft B/C

Postby MattChina » March 14th, 2018, 2:28 pm

Oh whoops, haha.
Find the final speed of a 100 kg roller coaster car that has dropped 50 m (from rest), gone back up 30 m, dropped 60 m, gone back up 30 m, and then at that level been pushed for 5 seconds with a force of 50 Newtons.
2.5 m/s
2019 events: Water Quality, Battery Buggy, Elastic Launch Glider, Density Lab, Circuit Lab, Thermodynamics
R.C Murphy Co-Captain
Dank Memes Area Homeschool Team member

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Hovercraft B/C

Postby UTF-8 U+6211 U+662F » March 14th, 2018, 2:35 pm

Oh whoops, haha.
Find the final speed of a 100 kg roller coaster car that has dropped 50 m (from rest), gone back up 30 m, dropped 60 m, gone back up 30 m, and then at that level been pushed for 5 seconds with a force of 50 Newtons.
2.5 m/s
No, not quite. Remember that the car has dropped and therefore gained speed.

MattChina
Member
Member
Posts: 224
Joined: February 12th, 2017, 8:06 am
Division: B
State: NY
Location: somewhere over the rainbow

Re: Hovercraft B/C

Postby MattChina » March 14th, 2018, 3:16 pm

Oh whoops, haha.
Find the final speed of a 100 kg roller coaster car that has dropped 50 m (from rest), gone back up 30 m, dropped 60 m, gone back up 30 m, and then at that level been pushed for 5 seconds with a force of 50 Newtons.
2.5 m/s
No, not quite. Remember that the car has dropped and therefore gained speed.
33.8m/s?
2019 events: Water Quality, Battery Buggy, Elastic Launch Glider, Density Lab, Circuit Lab, Thermodynamics
R.C Murphy Co-Captain
Dank Memes Area Homeschool Team member

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Hovercraft B/C

Postby UTF-8 U+6211 U+662F » March 14th, 2018, 3:18 pm

2.5 m/s
No, not quite. Remember that the car has dropped and therefore gained speed.
33.8m/s?
Yep (at least that's what I remember). Your turn!

MattChina
Member
Member
Posts: 224
Joined: February 12th, 2017, 8:06 am
Division: B
State: NY
Location: somewhere over the rainbow

Re: Hovercraft B/C

Postby MattChina » March 14th, 2018, 3:39 pm

A hovercraft with a mass of 100 kg going at 4m/s has its thrust turned off abruptly. It is traveling across the ice with a friction coefficient of 0.38. How far will it travel across the ice?
2019 events: Water Quality, Battery Buggy, Elastic Launch Glider, Density Lab, Circuit Lab, Thermodynamics
R.C Murphy Co-Captain
Dank Memes Area Homeschool Team member

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Hovercraft B/C

Postby UTF-8 U+6211 U+662F » March 14th, 2018, 6:53 pm

A hovercraft with a mass of 100 kg going at 4m/s has its thrust turned off abruptly. It is traveling across the ice with a friction coefficient of 0.38. How far will it travel across the ice?
a = 9.8 m/s^2 * 0.38 = 3.724 m/s^2
0 = (4 m/s)^2 - 2 * 3.724 m/s^2 * d
d = 2.15 m


Return to “2018 Question Marathons”

Who is online

Users browsing this forum: No registered users and 1 guest