# Maths

The average depth of the water in a port on a tidal river is 4 m. At low tide, the depth of the water is 2 m. One cycle is completed approx every 12 h. a) find an equation of the depth d(t) metres, with respect to the average depth, as a function of the time, t hours, after low tide, which occurred at 15:00.

1. 👍 0
2. 👎 0
3. 👁 252
1. Since it asks for depth wrt average, we do not need the 4 m average but only how much it departs from average

at t = 0, d = -2 (low tide, 2 feet below average)

d = -2 cos 2 pi t/T
since T = 12 hours is given
d = -2 cos (pi t/6)

1. 👍 0
2. 👎 0
posted by Damon
2. ok thanks a lot for your help :D

1. 👍 0
2. 👎 0
posted by Han

## Similar Questions

1. ### Trigonometric Functions

The average depth of the water in a port on a tidal river is 4m. At low tide, the depth of the water is 2m. One cycle is completed approximately every 12h. a)Find an equation of the depth, d(t)metres, with respect to the average

asked by Sam on April 30, 2014
2. ### Trig functions

The average depth of the water in a port on a tidal river is 4m. At low tide, the depth of the water is 2m. One cycle is completed approximately every 12h. a)Find an equation of the depth, d(t)metres, with respect to the average

asked by REALLY URGENT on April 30, 2014
3. ### math pls

Tidal forces are greatest when the Eaetg, the sun and the moon are in line. When this occurs at the Annapolis Tidal Generating Station, the waterhas a maximum depth of 9.6 m at 4:30 pm and a minimum depthof 0.4 m 6.2 hourslater.

asked by - on January 26, 2010
4. ### Science

In a tidal barrage scheme, the area of sea-water behind the barrage is 30km^2, tidal depth is 10m and the density of sea water is 1030kgm^-3. a. What energy is possible available from this scheme in one cycle of ebb and flow???

asked by Mariam on September 7, 2012
5. ### trig

On a typical day at an ocean port, the water has a maximum depth of 18m at 6:00 am. The minimum depth of 9m occurs 6.8 hours later. Write an equation to describe the relationship between the depth and time.

asked by Sam on April 29, 2014
1. ### physics

River A & B flow into river C. River A is 40 ft wide and is flowing at an average of 2.47 mph. River B is 25 ft wide and has a flow rate of 1125 cubic feet per second. Assume all rivers have a uniform depth of 15 ft. If river C is

asked by Brian on October 19, 2011

The depth d of water in a tank oscillates sinusoidally once every 4 hours. If the smallest depth is 7.9 feet and the largest depth is 10.1 feet, find a possible formula for the depth in terms of time t in hours. (Let the water

asked by Natalie on September 3, 2015
3. ### maths

the volume of water in a tidal pool is given by the formula V = 2cos (3pi/x ) where x is the depth of water in the pool. Find the water at which the depth of the pool will be increasing when the volume in the pool is increasing at

asked by Michelle on July 15, 2012
4. ### math

On a typical day at an ocean port, the water has a maximum depth of 20m at 8:00AM. The minimum depth of 8m occurs 6.2h later. Assume that the relation between the depth of the water and time is a sinusoidal function. write an

asked by sh on January 16, 2009
5. ### physics

At the bottom of river there is a lamp. On what minimal distance from the subject its reflection will be placed at the bottom of the river? Refraction index of water is 1.5, depth of the river is 2.5 m.

asked by Anonymous on December 4, 2011

More Similar Questions