An anchored fishing boat uses sonar to work out how deep would the water be if the echo took 2 seconds to return?

a) how deep is the water
b) if the boat was on a lake instead of the sea, how deep would the water be if the echo took 2 seconds to return.

c) why is it important that the sonar machine has the information about what kind of water the boat is in.

d) a little while later, the ultrasound machine detects two echoes from a ping, after 0.05 seconds and 0.7 seconds. suggest what these echoes mean..

i need the right answers for today

coil wire, increase current, put iron inside the coil

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.