can anyone explain how to do this

A spring is stretched by 175 mm an 8 kg block. If the block is displaced 100 mm downward from its equilibrium position and given a downward velocity of 1.50 m/s, determine the differential equation which describes the motion. Assume that positive displacement is downward. Determine the position of the block when the weight decreased from 8 kg until 4 kg?

[Jan]

Does this question have a relation to Matlab?

[Ahmed Moh'd Salem]

The quastion should be solved by using Matlab

Answer 1

[Jonas]

so if you put 8kg on the spring it moves 175mm down and does not move further. this means there is a force equlibrium between the weight and the spring which you can use to calculate the spring constant k

k*0.175m=8kg*9.81m/(s^2)

from that you can also solve the 4kg question

the motion will follow a cosine function A*cos(2*pi*f*t). the frequency is sqrt(k/m)/(2*pi), the amplitude is given and the starting speed gives you the condition for the dervative of the motion