The acceleration of a rocket traveling upward is given by a = (6 + 0.02s) m/s2 , where s is in meters. Determine the time needed for the rocket to reach an altitude of s = 100 m. Initially, v = 0 and s = 0 when t = 0.

Respuesta :

Answer:

It takes 5.755 seconds for the rocket to reach an altitude of s = 100m.

Explanation:

The velocity equation is the integrative of the acceleration equation.

The position equation is the integrative of the accelaration equation.

We have that:

[tex]a(t) = 6 + 0.02t[/tex]

The s there is wrong, m/s² means that it is a(t), not a(s), since s is in meters and t is in seconds.

The velocity is

[tex]v(t) = \int a(t) \, dt[/tex]

[tex]v(t) = \int (6 + 0.02t) \, dt[/tex]

[tex]v(t) = 6t + 0.01t^{2} + K[/tex]

In which K is the constant of integration. This is the initial velocity. We have that v = 0 when t = 0. So K = 0.

[tex]v(t) = 6t + 0.01t^{2}[/tex]

The position is the integrative of the velocity, so:

[tex]s(t) = \int v(t) \, dt[/tex]

[tex]s(t) = \int (6t + 0.01t^{2}) \, dt[/tex]

[tex]s(t) = 3t^{2} + 0.0033t^{3} + K[/tex]

In which K is the constant of integration. This is the initial position. We have that s = 0 when t = 0. So K = 0.

The equation for the position is:

[tex]s(t) = 3t^{2} + 0.0033t^{3}[/tex]

Determine the time needed for the rocket to reach an altitude of s = 100 m.

This is t when s = 100.

[tex]s(t) = 3t^{2} + 0.0033t^{3}[/tex]

[tex]3t^{2} + 0.0033t^{3} = 100[/tex]

[tex]0.0033t^{3} + 3t^{2} - 100 = 0[/tex]

We only use the positive roots, since the answer is an instant of time.

The answer is t = 5.755.

So it takes 5.755 seconds for the rocket to reach an altitude of s = 100m.