Intro to Impulse Video Lessons

Concept

# Problem: A boy of mass 64.7 kg is rescued from a hotel fire by leaping into a firefighters' net. The window from which he leaped was 8.9 m above the net. The firefighters lower their arms as he lands in the net so that he is brought to a complete stop in a time of 0.40 s. Ignore air resistance.What is the impulse on the net due to the boy during the interval (magnitude and direction)?

###### FREE Expert Solution

We'll use the kinematic equation:

$\overline{){{{\mathbf{v}}}_{{\mathbf{f}}}}^{{\mathbf{2}}}{\mathbf{=}}{{\mathbf{v}}_{\mathbf{0}}}^{{\mathbf{2}}}{\mathbf{+}}{\mathbf{2}}{\mathbit{a}}{\mathbit{s}}}$

In this problem:

The initial velocity, v0 = 0

Impulse = change in momentum.

99% (418 ratings)
###### Problem Details
A boy of mass 64.7 kg is rescued from a hotel fire by leaping into a firefighters' net. The window from which he leaped was 8.9 m above the net. The firefighters lower their arms as he lands in the net so that he is brought to a complete stop in a time of 0.40 s. Ignore air resistance.

What is the impulse on the net due to the boy during the interval (magnitude and direction)?