How can you determine what a physical change or a chemical change is? (obvious sign for both)

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?

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?

Which best describes the weak nuclear force? it maintains attraction between the m ecules in liquids. it attracts the nucleus of one atom to the nucleus of another atom. it pulls all matter in the universe together it keeps particles that make up protons and neutrons together