AP Physics B?

Question

Can anybody decipher #1 from the 2007 AP Physics B free response section? It is from
http://apcentral.collegeboard.com/apc/public/repository/ap07_physb_frq_kw.pdf
and I would appreciate some help! Thanks!

Answer 1

Here you are Nick:
the time it takes to travel 21 m under a constant velocity of 2.4 m/s is
21/2.4 seconds

The FBD will have m*g downward and friction parallel resisting motion

The force parallel to the slope pulling the sled is
sin(15)*m*g
and the force of friction is balancing it
cos(15)*m*g*µ
so
µ=tan(15)

once the sled is on level ground there is no force pulling it forward. The acceleration will be slowing the sled due to friction of
-g*µ (since friction is m*g*µ and F=m*a)
so
v(t)=2.4-g*µ*t

BTW: g is 9.8 m/s
j

Answer 2

I took AP Phys B in highschool and have been given a 4 on the examination. My college usual it no situation, yet once you want to be a physics significant extremely you will ought to take mechanics returned, this time employing calculus. you will ought to take calculus too, so in step with probability you should get that out of how (it is going to likely be usual no rely what in case you bypass the examination. additionally, be conscious that Physics C would be very difficult and not employing a calc history.

Answer 3

I haven't consulted apcentral but believe that AP Physics B gives "second college semester" credit for Physics if the student scores a 3 (or better) out of a possible 5 on the test. It's NOT an easy test. (from a former physics major)