- #1
kubaanglin
- 47
- 5
Homework Statement
Relative motion problem:
A child in danger of drowning in a river is being carried downstream by a current that has a speed of 2.4 km/h. The child is .3 km from the shore and .4 km upstream of a boat landing where a rescue boat sets out.
a) If the boat proceeds at a maximum speed of 20 km/h relative to the water, what heading should the boat take relative to the shore?
I got 36.87 degrees from positive x-axis
b)What angle does the boat's velocity with respect to the Earth make relative to the shore?
I got 41.4 degrees from positive x-axis
c) How long does it take the boat to reach the child?
I got 1.5 min (.025 hours)
d) If the child swims upstream at 1.3 km/h instead of just floating motionless in the water, how should the rescue boat change its heading to reach the child as quickly as possible?
I am having trouble with this one.
Homework Equations
None come to mind.
The Attempt at a Solution
I have been struggling with this for the past 30 minutes. I know that the angle will be just slightly less than the angle in the answer to question a, but I have tried drawing multiple triangles with the perspective of the child in mind and have not been able to figure this problem out. I have a chapter test on projectile motion, radial motion, and relative motion tomorrow and am sure there will be a problem like this on the test. Any help will be greatly appreciated.
Thank you,
Kuba