# Problem: Assume that the conditions are as in Problem 20 [a ball with mass 0.15kg is thrown upward with initial velocity 20 m/s from the roof of a building 30 m high] except that there is a force due to air resistance of magnitude|v|/30 directed opposite to the velocity, where the velocity v is measured in m/s.(a) Find the maximum height above the ground that the ball reaches.(b) Find the time that the ball hits the ground.

###### FREE Expert Solution

Gravitational force is expressed as:

$\overline{){{\mathbf{F}}}_{{\mathbf{g}}}{\mathbf{=}}{\mathbf{m}}{\mathbf{g}}}$

From the variables given, gravitational force, Fg = (0.15)(-9.8)

Fg = - 1.47 N

The force due to air resistance is:

Fa = |v|/30.

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###### Problem Details

Assume that the conditions are as in Problem 20 [a ball with mass 0.15kg is thrown upward with initial velocity 20 m/s from the roof of a building 30 m high] except that there is a force due to air resistance of magnitude|v|/30 directed opposite to the velocity, where the velocity v is measured in m/s.

(a) Find the maximum height above the ground that the ball reaches.

(b) Find the time that the ball hits the ground.