If 600J of work is performed sliding a 12 kg box across a concrete floor and friction roduces heat/sound ener: of 465 J what will be the veloci of the ob'ect? 

 If 600J of work is performed sliding a 12 kg box across a concrete floor and friction roduces heat/sound ener: of 465 J what will be the veloci of the ob'ect? 
. The speed of sound in air is 343 m/s and in water is 1450 m/s. A monotone speaker is producing a sound at a frequency of 752 Hz. What are the wavelengths produced by this s eaker in air and in water? 

A 170 g cue ball travelling at 2.1 m/s collides with a 160 g billiard ball travelling towards it at 3.6 km/hr. If the cue ball is stationary after the collision, find the final velocity of the billiard ball, and amount of kinetic energy lost in the collision. (Hint make sure you do a sign convention, write down all known and unknows and convert to SI units, and write down any assumptions) 
A "doors off' helicopter has risen to 135m high. A person aboard while taking a picture, drops their phone weighing 157 g. Assuming the object starts at rest, find (a) What is the potential energy of the phone before it left her hand? (b) What is the velocity at which it hits the ground? (use conservation of energy with no air resistance) (c) If impact time is three milliseconds, determine the average force on the phone. (hint - im ulse