I am stuck on a problem from the 5 Steps to a 5: AP Physics B&C book and would really appreciate anyone's help.
1. The problem statement, all variables and given/known data
Determine (a) the acceleration of the block down the plane and (b) the time for the block to slide to the bottom of the plane.
2. Relevant equations
F=ma
F, gravity = mg
F, friction = umg
Kinematic equation ???
3. The attempt at a solution
Fx, up the plane = mgsin25 + umgcos25 = 204 N
a = F/m = 204/30 = 6.8 m/s^2
Fx, down the plane = mgsin25 - umgcos25 = 44 N
a = F/m = 44/30 = 1.5 m/s^2
I tried using x = Vot + 1/2 at^2 (x = 20 m, Vo = 3m/s) and v = Vo + at (v = 0, Vo = 3 m/s) to solve for time, but my answers were way off on both attempts.
1. The problem statement, all variables and given/known data
Determine (a) the acceleration of the block down the plane and (b) the time for the block to slide to the bottom of the plane.
2. Relevant equations
F=ma
F, gravity = mg
F, friction = umg
Kinematic equation ???
3. The attempt at a solution
Fx, up the plane = mgsin25 + umgcos25 = 204 N
a = F/m = 204/30 = 6.8 m/s^2
Fx, down the plane = mgsin25 - umgcos25 = 44 N
a = F/m = 44/30 = 1.5 m/s^2
I tried using x = Vot + 1/2 at^2 (x = 20 m, Vo = 3m/s) and v = Vo + at (v = 0, Vo = 3 m/s) to solve for time, but my answers were way off on both attempts.
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