Consider a system consisting of a smooth pulley with two masses suspended from e
ID: 1499265 • Letter: C
Question
Consider a system consisting of a smooth pulley with two masses suspended from each end. Find a and b.
Problem 1: Consider a system consisting of a smooth pulley with two masses (m and m2, withm > m2) suspended from a light string at each end. (See Fig. 1 below.) Find: (a) an expression for the acceleration of mass 1; (b) an expression for the acceleration of mass 2; and (c) an expression for the magnitude of the tension Fr of the string. All forces to be considered are shown in the figure. +Z F. m.2 g2Explanation / Answer
let the acceleration of m1 is 'a1' (to down) and acceleration of m2 is 'a2' (to up).
then equation of m1
Fg1 - Ft = m1a1
m1g - Ft = m1a1
a1 = g - Ft/m1 ... (1)
now equation for m2
Ft - Fg2 = m2a2
Ft - m2g = m2a2
a2 = (Ft/m2) - g
both acceleration should be equal
g - Ft/m1 = (Ft/m2) - g
2g = Ft/m1 + Ft/m2
2g = Ft*(m1 + m2)/m1*m2
Ft = 2g*m1*m2/(m1 + m2)
now a1 = g - Ft/m1 = g - 2g*m2/(m1 + m2) = g*(m1 - m2)/(m1 + m2)
a2 = (Ft/m2) - g = 2g*m1/(m1 + m2) - g = g*(m1 - m2)/(m1 + m2)