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agreed
It was easy. That means the curve is gonna be high. :|
What did you get for P? What did you get for the angle for the impulse question and the angle for the centre of mass question?
impulse 63 and COM 14 (cant remember dp)
imasillynarb
What did you get for P? What did you get for the angle for the impulse question and the angle for the centre of mass question?

0.4mg < P < 13.6mg

The angle for the impulse question was somewhere around 60-80, and the angle for the CM question was somewhere between 15-25. I don't really remember.
shift3
< P < 13.6

The angle for the impulse question was somewhere around 60-80, and the angle for the CM question was somewhere between 15-25. I don't really remember.

I got 14.6 I think for the COM question, and 40.3 I think for the impulse angel...

How did you find P?
i didnt!
imasillynarb
What did you get for P? What did you get for the angle for the impulse question and the angle for the centre of mass question?

P is greater than or equal to 0.4mg

angle for impulse: 63.43 degrees

angle for C of M: 14.6 degrees

(i think)
yea that sounds like the angles i got
imasillynarb
I got 14.6 I think for the COM question, and 40.3 I think for the impulse angel...

How did you find P?

Assume two cases, one where the friction is in the same direction as P, and one where it's opposite.

friction < 0.6 * 11mg (6.6mg)
and t=5/2 in the vectors. t=3 in the last question. distance 48m in last question. 0.7 for the first...COM was at 5/6 from BC
Ermmm... P is between 1.95mg and 6.3mg....

I'm certainly wrong on that one then!!!

Anyway, ce la vis!
I did well enough on the rest of it!
sam99
angle for impulse: 63.43 degrees

angle for C of M: 14.6 degrees

Yup
Impulse question was quite easy to make a mistake on I reckon..

P = 0.4mg, I got that as well, except theyre not going to give you 7 marks for rearraging F + P = N

So that ones wrong.

As with the impulse question, it wanted the angle of projection. The balls comes in at 30i and is projected at root(5^2 + 25^2???), so you wanted the angle between the resultant and the 30i, not the angle between 5 and 25, I think
Sapphira
and t=5/2 in the vectors. t=3 in the last question. distance 48m in last question. 0.7 for the first...COM was at 5/6 from BC

Yeah, and the last part of question 7 (the last question) was ~23.6.

For the first question I got a=1.2, I don't know where I messed up.
shift3
Assume two cases, one where the friction is in the same direction as P, and one where it's opposite.

friction < 0.6 * 11mg (6.6mg)

Err, why do you assume 2 cases? You know which way the friction acts. Its not a 'maybe' ...
lol dont worry was prob me that messed up, im particularly crap at maths
Sapphira
lol dont worry was prob me that messed up, im particularly crap at maths

Your answer is right, all my friends got 0.7.
imasillynarb
Err, why do you assume 2 cases? You know which way the friction acts. Its not a 'maybe' ...

Friction acts opposite to motion. In the default case, it acts opposite to the motion of the ladder, i.e. to the right. However, when P becomes strong enough to break equilibrium, friction acts opposite to it, i.e. to the left.