# Calculus question

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#1
A boat is held by a bow line that is wound around a bollard 4 metres higher than
the bow of the boat. If the boat is drifting away at the rate of 8 metres per minute,
how fast is the line unwinding when the bow is exactly 20 metres from the bollard?
how do i do this question
0
3 years ago
#2
A boat is held by a bow line that is wound around a bollard 4 metres higher than
the bow of the boat. If the boat is drifting away at the rate of 8 metres per minute,
how fast is the line unwinding when the bow is exactly 20 metres from the bollard?
how do i do this question
Let x be the horizontal distance from the bow to the bollard. Now derive an equation for the length of (infinitely taut) line from the bow to the bollard. Differentiate that to get its rate of change.
Last edited by RogerOxon; 3 years ago
1
#3
(Original post by RogerOxon)
Let x be the horizontal distance from the bow to the bollard. Now derive an equation for the length of (infinitely taut) line from the bow to the bollard. Differentiate that to get its rate of change.
I dont understand How I'd derive an equation
0
3 years ago
#4
I dont understand How I'd derive an equation
It's a triangle. You need an equation for the hypotenuse.
0
3 years ago
#5
I dont understand How I'd derive an equation
Here's a start:
0
#6
shouldnt it be y=x^2+4^2
or am i confused
0
#7
(Original post by RogerOxon)
Here's a start:
^^^^^^^^
0
3 years ago
#8
shouldnt it be y=x^2 4^2
or am i confused
Yes, you're right. The constant will disappear though, not that I should have missed the power ..
Last edited by RogerOxon; 3 years ago
0
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