Post by: fredrick on April 27, 2008, 06:56:05 pm
[IMG]http://img80.imageshack.us/img80/4624/physoq8.jpg[/img]
Post by: iamdan08 on April 27, 2008, 07:44:58 pm
Knowing this:
Subtract the retarding force:
Post by: Mao on April 27, 2008, 08:51:16 pm
This question is from the 2005 exam. There is information prior to this question which states the mass of the rocket is 0.2 kg.
didnt checkpoints include this?
easier method:
net retardation:
net acceleration = g - retardation
Post by: fredrick on April 27, 2008, 08:53:56 pm
Post by: iamdan08 on April 27, 2008, 08:54:07 pm
Post by: Mao on April 27, 2008, 08:54:41 pm
I wonder what they'll do next!
Post by: fredrick on April 27, 2008, 08:56:39 pm
they even fail at copy-pasting....
I wonder what they'll do next!
L0L
Post by: ed_saifa on April 27, 2008, 08:59:40 pm
Post by: Mao on April 27, 2008, 09:13:26 pm
Told you physics was ambiguous. Amazing how so many people in my class managed to do it without this information..what!
what was the answer?
Post by: fredrick on April 27, 2008, 09:15:13 pm
Post by: dcc on April 27, 2008, 09:21:33 pm
Parachutes cannot provide an acceleration upwards for a long amount of time, so that flattening out suggest that terminal velocity has been reached.
One would only make assumptions like these if you didn't have the mass defined for you, because its risky business.
p.s. since the rocket would presumably be a small object, there is no worry that the parachute has just reached its 'maximum retardation force', but rather that it cannot retard any more
Post by: iamdan08 on April 27, 2008, 10:36:01 pm
As the curve of retarding force levels out at 2N, it is a safe assumption to make that this is the point when, which means that you can make your retarding force equal to the weight force, which gives the 0.2kg mass as required.
Hmmm. That is a good point.
Post by: Captain on April 28, 2008, 06:10:25 pm
As the curve of retarding force levels out at 2N, it is a safe assumption to make that this is the point when
Parachutes cannot provide an acceleration upwards for a long amount of time, so that flattening out suggest that terminal velocity has been reached.
One would only make assumptions like these if you didn't have the mass defined for you, because its risky business.
p.s. since the rocket would presumably be a small object, there is no worry that the parachute has just reached its 'maximum retardation force', but rather that it cannot retard any more
That's how I did it. :)
Btw fredrick, by this stage of the year, you should be way further ahead in your checkpoints. Spend one weekend to catch up :P