- #1
Becca93
- 84
- 1
Homework Statement
A block with mass m = 7.4 kg slides down an inclined plane of slope angle 43.8 ° with a constant velocity. It is then projected up the same plane with an initial speed 3.10 m/s. How far up the incline will the block move before coming to rest?
The attempt at a solution
You need to find the force parallel of the block on the incline, so
Fpara = mgsinθ
Fpara = (7.4)(9.8)sin(43.8)
Fpara = 50.194 N
Acceleration down is
a = F/m
a = 50.194/7.4
a = 6.783
If the block begins moving up at Vi = 3.10 m/s, and Vf = 0, then
Vf^2 = Vi^2 + 2ad
0 = 3.1^2 + (2)(-6.783)d
d = -(3.1)^2 / -13.566
d = 0.708
This is not correct. Obviously, I'm doing this wrong, but I'm not sure of any other way to do it. I feel like having such a large acceleration down can't possibly be correct, and if that is indeed the case, how do I find acceleration of the block as it goes up the incline?
A block with mass m = 7.4 kg slides down an inclined plane of slope angle 43.8 ° with a constant velocity. It is then projected up the same plane with an initial speed 3.10 m/s. How far up the incline will the block move before coming to rest?
The attempt at a solution
You need to find the force parallel of the block on the incline, so
Fpara = mgsinθ
Fpara = (7.4)(9.8)sin(43.8)
Fpara = 50.194 N
Acceleration down is
a = F/m
a = 50.194/7.4
a = 6.783
If the block begins moving up at Vi = 3.10 m/s, and Vf = 0, then
Vf^2 = Vi^2 + 2ad
0 = 3.1^2 + (2)(-6.783)d
d = -(3.1)^2 / -13.566
d = 0.708
This is not correct. Obviously, I'm doing this wrong, but I'm not sure of any other way to do it. I feel like having such a large acceleration down can't possibly be correct, and if that is indeed the case, how do I find acceleration of the block as it goes up the incline?