A referee runs towards you while blowing a whistle, resulting in a sound with a greater pitch than when you heard the whistle at halftime and the referee was stationary. What is this an example of? *

If 21.2 kcals of energy is released by this reaction, how many kj does the reaction release? (1 cal 4.184 j)

True or false when elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?