You have a two-wheel trailer that you pull behind your ATV. Two children with a combined mass of 77.2 kg hop on board for a ride through the woods and the springs (one for each wheel) each compress by 6.37 cm. When you pull the trailer over a tree root in the trail, it oscillates with a period of 2.14 s. Determine the following.
(a) force constant of the springs 2274.43 X How is the force constant of a spring related to the force the spring exerts when it is stretched or compressed? N/m
(b) mass of the trailer kg
(c) frequency of the oscillation Hz
(d) time it takes for the trailer to bounce up and down 10 times.

Respuesta :

To solve this problem it is necessary to apply the kinematic equations of motion and Hook's law.

By Hook's law we know that force is defined as,

[tex]F= kx[/tex]

Where,

k = spring constant

x = Displacement change

PART A) For the case of the spring constant we can use the above equation and clear k so that

[tex]k= \frac{F}{x}[/tex]

[tex]k = \frac{mg}{x}[/tex]

[tex]k= \frac{77.2*9.8}{0.0637}[/tex]

[tex]k = 11876.92N/m[/tex]

Therefore the spring constant for each one is 11876.92/2 = 5933.46N/m

PART B) In the case of speed we can obtain it through the period, which is given by

[tex]T = \frac{2\pi}{\omega}[/tex]

Re-arrange to find \omega,

[tex]\omega = \frac{2\pi}{T}[/tex]

[tex]\omega = \frac{2\pi}{2.14}[/tex]

[tex]\omega = 2.93rad/s[/tex]

Then through angular kinematic equations where angular velocity is given as a function of mass and spring constant we have to

[tex]\omega^2 = \frac{k}{m}[/tex]

[tex]m = \frac{k}{\omega^2}[/tex]

[tex]m = \frac{ 11876.92}{2.93}[/tex]

[tex]m = 4093.55Kg[/tex]

Therefore the mass of the trailer is 4093.55Kg

PART C) The frequency by definition is inversely to the period therefore

[tex]f = \frac{1}{T}[/tex]

[tex]f = \frac{1}{2.14}[/tex]

[tex]f = 0.4672 Hz[/tex]

Therefore the frequency of the oscillation is 0.4672 Hz

PART D) The time it takes to make the route 10 times would be 10 times the period, that is

[tex]t_T = 10*T[/tex]

[tex]t_T = 10 *2.14s[/tex]

[tex]t_T = 21.4s[/tex]

Therefore the total time it takes for the trailer to bounce up and down 10 times is 21.4s