Question

What must be the mass m2m2 of the hanging block if it is to descend 10.0 mm in the first 3.00 ss after the system is released from rest?

Answer 1

Answer:

m = 20[kg]

Explanation:

This problem can be solved, using kinematic equations and then applying Newton's second law. First we must find the acceleration and then replace it in the equation of Newton's second law.

Initial data:

Vo = initial velocity = 0 [m/s]

t = 3[s]

$y=v_{o}*t+0.5*a*t^2\\0.01=0.5*a*(3)^2\\a=0.0022[m/s^2]$

T- F = -m*a

T - m*g = m*a

We can assume a value for tension T equal to 196 [N].

$m=\frac{T}{g-a}\\ m=\frac{196}{9.81-0.00222}\\m=20[kg]$

Note: For this problem it is important to assume a tension value, otherwise, it is impossible to determine the value of mass m, in Newton's second law equation.