Please answer the equestrians in the picture, if it’s not clear enough I have the questions down below: 2. You click your fingers in a large hall and hear the echo 0.5 seconds later off the back wall. How far is the back wall?

3. A boat sends a sound to the bottom of the ocean and it takes 2 seconds to return to the boat. How deep in the ocean?

An explanation would be great too :)

15 points awarded

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz.

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?