A runner is jogging in a straight line at a steady vr= 8.4 km/hr. When the runner is

L= 6.3 km from the finish line, a bird begins

flying straight from the runner to the finish

line at vb= 42 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.

Total distance traveled by bird is 10.5 km.

Explanation:

Given that,

Velocity of runner= 8.4 km/hr

Distance = 6.3 km

Velocity of bird = 42 km/hr

Suppose, How far does the bird travel?

We need to calculate the time of bird

Using formula of time

Put the value into the formula

We need to calculate the distance runner travels during time period

Using formula of distance

We need to calculate the distance of runner to FL

Using distance

We need to calculate the net closing speed between runner and bird

Using speed

We need to calculate the time for runner and bird to meet

Using formula of time

Put the value into the formula

We need to calculate the distance covered by runner

Using formula of distance

Put the value into the formula

We need to calculate the distance covered by bird to runner

Using formula of distance

Put the value into the formula

We need to calculate the total distance

Using distance

Hence, Total distance traveled by bird is 10.5 km.

moving ball hits still ball. mover stops, hit ball moves. momentum transfer.