2013 Invitational A #51,52

[martillaso]

51. A 7.0 kg block, initially at rest, is pulled with a constant horizontal force of 14N to the right. Find the block's speed after it has traveled 2.0m if the coefficient of kinetic friction is 0.17.

a) 1.2 m/s
b) 2.7 m/s
c) 3.2 m/s
d) 7.3 m/s
e) 13 m/s

For this one I got 2.38 N for the net force and .34 m/s^2 for acceleration but after that I'm stumped.

52. A uniform ladder of length, l, and mass, m, rests against a very smooth, vertical wall. If the coefficient of static friction between the ladder and the ground is mu_s=0.320, what is the minimum angle theta at which the ladder remains at rest?

a) 1.63
b) 32.6
c) 39.8
d) 57.4
e) 88.4

I don't know where to start with this one. I drew a free body diagram, but I can't see how to solve it.

I know these are probably really easy, but I won't see my coach this week before Districts so I'd appreciate if any of you guys could help me out,

[darksaber21]

[martillaso]

Wooow yeah I didn't realize that was a kinematic q. I only have 2 of the equations memorized, I should work on that. I'm still confused on the ladder one though

[darksaber21]