I am having a hard time finding the formula for acceleration constraints. I understand Newton's Third law, but I can't seem to find the numbers. More specifically I need to find if you have a Mass on a Frictionless table attached to a Massless rope, strung over a frictionless pulley and another Mass dangling from the rope, how would you find the accleration?
Acceleration Constraints, Physics Help please
-
-
im not 100% sure…but i think the acceleration would just be the mass dangling from the rope times gravity
-
acceleration is not a constraint.
to solve that problem, use newton's 2nd law. let m1 be the mass on the table and m2 be the mass dangling down. since there is no friction, we don't need to worry about normal forces.
on m1, the forces acting on it is the tension on the string. on m2, the forces acting on it is m2*g pointing down, and tension pointing up. so you use newton's 2nd law and sum up the forces.
sum of F = m_total*a
- T - T + m2*g = (m1+m2)a
m2g = (m1+m2)*a
a = m2*g / (m1+m2)
- T - T + m2*g = (m1+m2)a
-
Thanks e1n, thats what I was looking for. My physics book wasn't really explaining things and my professor doesn't explain anything either.