Question

A runner is jogging in a straight line at a
steady vr= 5.9 km/hr. When the runner is
L= 6.6 km from the finish line, a bird begins
flying straight from the runner to the finish
line at vb= 29.5 km/hr (5 times as fast as
the runner). When the bird reaches the finish
line, it turns around and flies directly back to
the runner.
What cumulative distance does the bird
travel? Even though the bird is a dodo, assume that it occupies only one point in space
(a “zero” length bird), travels in a straight
line, and that it can turn without loss of
speed.
Answer in units of km.

Answer 1

Answer:

33 km.

Explanation:

In the question,

Speed of the runner = 5.9 km/hr.

Distance of the runner from the finish line = 6.6 km

Speed of the bird = 29.5 km/hr.

As,

The bird doesn't stop and flies constantly, the distance covered by the bird can be given by the product of the time taken by the runner to the finish line and the speed of the bird.

i.e.

Distance covered by the bird = Speed of the bird x Time taken by the runner

So,

Time taken by the runner to reach the finish line is,

$Time =\frac{Distance}{Speed}\\Time=\frac{6.6}{5.9}\\Time=1.118\,hr.$

So,

Distance covered by the bird is,

$Distance =Speed\times Time\\Distance=29.5\times 1.118\\Distance=33\,km$

Therefore, the Distance covered by the bird is 33 km.