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A 1.2-kg mass is projected from ground level with a velocity of 30 m/s at some unknown angle above the horizontal. A short time after being projected, the mass barely clears a 16-m tall fence. Disregard air resistance and assume the ground is level. What is the kinetic energy of the mass as it clears the fence

Respuesta :

Answer:

[tex]K_f[/tex] = 351.84 J

Explanation:

Using the conservation of energy K:

[tex]E_i = E_f[/tex]

so:

[tex]\frac{1}{2}mv^2 = K_f + mgh[/tex]

where m is the mass, v the initial velocity, [tex]K_f[/tex] is the kinetic energy of the mass as it clears the fence, g the gravity and h the altitude.

Then, replacing values, we get:

[tex]\frac{1}{2}(1.2kg)(30m/s)^2 = K_f + (1.2kg)(9.8m/s^2)(16m)[/tex]

solving for [tex]K_f[/tex]:

[tex]K_f[/tex] = 351.84 J

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