A 7.5 kg stone moves up frictionless hill that slopes upward at 41 above the horizontal. If the stone has a initial velocity of 8.5 m/s at the bottom, how far (as measured along the surface of the hill) will it go before stopping?

Respuesta :

Answer:

The stone will reach 3.2 m along the surface of the hill before stopping.

Explanation:

Let the height reached by the stone be 'h' m

Given:

Mass of the stone is 7.5 kg.

Angle of inclination is, [tex]\theta = 41\°[/tex]

Initial velocity of the stone at the bottom is, [tex]v=8.5\ m/s[/tex]

Final velocity of the stone at the top is 0 m/s.

Now, as per conservation of energy principle, sum of total energy is always conserved. Therefore, decrease in kinetic energy is equal to the increase in its potential energy.

Increase in Potential Energy = Decrease in Kinetic Energy

⇒ [tex] mgh = \frac{1}{2}mv^2[/tex]

⇒ [tex] gh=  \frac{1}{2}v^2[/tex]

⇒ [tex]h=\frac{v^2}{2g}[/tex]

Plug in the given values and solve for 'h'. This gives,

[tex]h=\frac{8.5^2}{2\times 9.8}=3.686\ m[/tex]

Now, slant height is given using the trigonometric ratio. The slant length 'L' is the hypotenuse and 'h' is the opposite side. Therefore,

[tex]\tan \theta=\frac{L}{h}\\\\L=h\times \tan\theta\\\\L=3.686\times \tan(41)\\\\L=3.2\ m[/tex]

Therefore, the stone will reach 3.2 m along the surface of the hill before stopping.

Ver imagen DarcySea