On a sunny day, a distracted driver on his cellphone noticed a tree way too late. He screeches as he slowed down but still hit the tree at 20 km/h. Afterwards, it was measured that he left a tire mark of 6.0 m in length (tire marks for only front tires drawn above). a) Calculate the car’s speed, in km/h, before the driver started slowing down. Define a system, draw energy state diagrams, and include a FBD for any forces. b) If this happened on an uphill slope of 6°, what would have been the car’s initial speed in km/h?

An object moves from the position +34m to the position -15m in 15 seconds. what is it's total displacement? what is it's average velocity?

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up