A toy rocket is launched with an initial velocity of 10.0 m/s in the horizontal direction from the roof of a 30.0 m -tall building. The rocket's engine produces a horizontal acceleration of (1.60 m/s3)t, in the same direction as the initial velocity, but in the vertical direction the acceleration is g , downward. Air resistance can be neglected.
What horizontal distance does the rocket travel before reaching the ground?

Respuesta :

Answer:

The toy rocket will do an horizontal distance of 27.793 meters before reaching the ground.

Explanation:

This rocket experiments a two-dimension motion consisting in a combination of vertical free-fall and a horizontal uniformly acclerated motion. Flight time is governed by vertical movement and can be found by using this formula:

[tex]y = y_{o}+v_{o,y}\cdot t +\frac{1}{2}\cdot g \cdot t^{2}[/tex]

Where:

[tex]y_{o}[/tex] - Initial height, measured in meters.

[tex]v_{o,y}[/tex] - Initial vertical speed, measured in meters per second.

[tex]t[/tex] - Time, measured in seconds.

[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.

[tex]y[/tex] - Current height, measured in meters.

If we know that [tex]y_{o} = 30\,m[/tex], [tex]v_{o,y} = 0\,\frac{m}{s}[/tex], [tex]g = -9.807\,\frac{m}{s^{2}}[/tex] and [tex]y = 0\,m[/tex], then resulting polynomial is solved:

[tex]0\,m = 30\,m +\left(0\,\frac{m}{s} \right)\cdot t +\frac{1}{2} \cdot \left(-9.807\,\frac{m}{s^{2}} \right)\cdot t^{2}[/tex]

[tex]30 - 4.905\cdot t^{2} = 0[/tex]

The time taken by the toy rocket is:

[tex]t \approx 2.407\,s[/tex]

Now, the horizontal distance can be found by integrating acceleration function twice. That is:

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

[tex]v(t) = 1.60\int {t} \, dt[/tex]

[tex]v(t) = 0.80\cdot t^{2}+v_{o}[/tex]

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

[tex]s(t) = \int {(0.80\cdot t^{2}+v_{o})} \, dt[/tex]

[tex]s(t) = 0.80\int {t^{2}} \, dt + v_{o}\int\, dt[/tex]

[tex]s(t) = 0.267\cdot t^{3} + v_{o}\cdot t + s_{o}[/tex]

If we know that [tex]v_{o} = 10\,\frac{m}{s}[/tex] and [tex]s_{o} = 0\,m[/tex], then the horizontal position formula is:

[tex]s(t) = 0.267\cdot t^{3}+10\cdot t[/tex]

Where:

[tex]s(t)[/tex] - Horizontal position, measured in meters.

[tex]t[/tex] - Time, measured in seconds.

Now, the horizontal distance before reaching the ground is found: ([tex]t \approx 2.407\,s[/tex])

[tex]s(2.407\,s) = 0.267\cdot (2.407\,s)^{3}+10\cdot (2.407\,s)[/tex]

[tex]s (2.407\,s) = 27.793\,m[/tex]

The toy rocket will do an horizontal distance of 27.793 meters before reaching the ground.