- #1
gijungkim
- 50
- 2
Homework Statement
The system shown is released from rest and moves 50 cm in 1.0 s. What is the value of M? All surfaces are frictionless.
X = 0.5 m
t = 1sec
m1 = 3kg
m2 = M
However, my question is about the acceleration. I'm just curious why I cannot use vf = v0 + at equation instead of x = x0 + v0t + 0.5at^2
Homework Equations
x = x0 + v0t + 0.5at^2
vf = v0 + at
The Attempt at a Solution
X = X0 + V0t + 0.5at^2
0.5m = 0 + 0 + 0.5a(1)^2
a=1m/s^2
M*g = (3kg + M)a
M(g-a) = 3a
M = 3a/(g-a) = 0.34kg
So I got M = 0.34kg. I know this is the answer but now my question is the acceleration.
I know I got 1m/s^2 from X = X0 + V0t + 0.5at^2 equation, but why can I not use Vf = V0 + at equation?
If I use Vf = V0 + at then I get a=0.5m/s^2 since vf = 0.5m/s and v0 = 0m/s and t=1.
Why do they have different acceleration?