In the diagram, sonar is used to locate a sunken ship. If the sonar echo is heard after 3 seconds, how long did it take for the signal to reach the sunken ship? Why?

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?