PLEASEPLEASEPLEASE HEL what information does a ship's sonar device use to determine the distance to the ocean?
a. the speed of sound in water and the time it takes for a signal to return
b. the temperature of the water and the temperature of the air above it
c. the composition of the ocean floor and the temperature of water near the ocean floor
d. the composition of the ocean floor and the temperature of water near the ocean floor
( i know there are two of the same answers but um that's how it was so)

Select the correct answer. anna will wear a black dress when she attends het cousin's wedding. which color(s) does the dress absorb? a. all colors b. no colors c. red and green d. white

Will you chech and finish these for me, because i am stumped with them.

Asquare 1m x 1m plate is shown below. all four of its edges are kept at 0 co. at t=0the temperature distribution is given by: y xtsins n75)=.a) using separation of variables determine the temperature distribution t(x,y,t)along the plate at any time t.b) discretize the heat conduction equation +=22222 txtusing a second-order centered difference scheme for the two second derivatives and a first-order forward euler scheme for the first derivative. using von neumann stability analysis, determine the stability criterion for the proposed discretization scheme in terms of , hand t. solve for the maximum allowable time step tmax