The echo sounder in a ship sends a burst of sound waves towards the seabed. 0.2 seconds later, reflected waves are picked up by the ship.

In which of the following cases is work being done on an object? question 2 options: pulling a trailer up a hill carrying a box down a corridor suspending a heavy weight with a strong chain pushing against a locked door

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?

An important dimensionless parameter concerned with very high-speed flow is the mach number, defined as v/c, where v is the speed of the object such as an airplane or projectile, and c is the speed of sound in the fluid surrounding the object. for a projectile traveling at 1170 mph through air at 50 ˚f and standard atmospheric pressure, what is the value of the mach number?