Your friend you place a 105 kg sofa in the back of a 2600 kg truck. your keen vision tells you that the truck sinks 3.5 cm on its springs when you place the sofa. with what frequency (in hz) will the truck and the sofa oscillate on the springs?

To develop this problem it is necessary to apply the concepts related to frequency from Hooke's law.

By Hooke's law we know that the Force is defined as

Where,

k = Spring constant

Displacement

at the same time Force can be defined by Newton's second law as,

F = mg

Where,

m = mass

g = gravity

Equating we have

Frequency and oscillation can be defined as

Then replacing,

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees. 

v=ir = 3x15 =45 v