A lighthouse is located on a small island 3 km away from the nearest point P on a straight shoreline and its light makes four revolutions per minute. How fast is the beam of light moving along the shoreline when it is 1 km from P?

answer

watching

views

For unlimited access to Homework Help, a Homework+ subscription is required.

You have 0 free answers left.
Get unlimited access to 3.8 million step-by-step answers.

Get unlimited access

Already have an account? Log in

Keith LeannonLv2

20 May 2020

Unlock all answers

Get 1 free homework help answer.

Already have an account? Log in

Related questions

Ornithologists have determined that some species of birds tend to avoid flights over large bodies of water during daylight hours. It is believed that more energy is required to fly over water than over land because air generally rises over land and falls over water during the day. A bird with these tendencies is released from an island that is 5 km from the nearest point B on a straight shoreline, flies to a point C on the shoreline, and then flies along the shoreline to its nesting area D. Assume that the bird instinctively chooses a path that will minimize its energy expenditure. Points B and D are 13 km apart.

(a) In general, if it takes 1.4 times as much energy to fly over water as it does over land, to what point C should the bird fly in order to minimize the total energy expended in

returning to its nesting area?

(b) Let W and L denote the energy (in joules) per kilometre flown over water and land, respectively. What would a large value of the ratio W/L mean in terms of the bird’s

flight? What would a small value mean? Determine the ratio W/L corresponding to the minimum expenditure of energy.

(c) What should the value of W/L be in order for the bird to fly directly to its nesting area D? What should the value of W/L be for the bird to fly to B and then along the shore to D?

copperscorpion335

2. (10 marks The circle below represents a record which is rotating clockwise at 100/3 revolutions per minute. A bug is walking away from the centre of the record directly toward point P on the rim of the record at 1 cm/s. When the bug is at position R, 10 cm from O, the angle 8 is 7/4 radians. Find the rate at which the distance from the bug to the fixed point Q is changing when the bug is at R. Simplify as much as possible but your final expression may contain square roots or well-known constants (such as it or e).

A street light is mounted at the top of a 15 ft tall pole. A man 6 ft tall walks away from the pole with a speed of 5 ft/s along a straight path. How fast is the tip of the his shadow moving when he is 40 ft from the pole .

(a) What quantities are given in the problem?

(b) What is the unknown?

(d) Write an equation that relate the quantities.

(e) Finish solving the problem

lemonbee169

Weekly leaderboard

Home

Homework Help 3,900,000

Mathematics 240,000