Reggie and charlotte are baking oatmeal cookies. they dip the baked cookies in melted chocolate. the chocolate cools to form a hardened coating. reggie argues the entire chocolate-covered cookie has undergone a chemical change. charlotte disagrees, saying only the original oatmeal cookie has undergone a chemical change, not the chocolate coating.

who is correct?

a: reggie, because baking and melting cause bonds to be broken, leading to a chemical change.
b: reggie, because objects that are heated always undergo chemical changes.
c: charlotte, because melting objects only sometimes cause a chemical change.
d: charlotte, because baking causes a chemical change, but melting objects is a non-chemical change.

Aball is thrown straight up into the air with a speed of 21 m/s. if the ball has a mass of 0.1 kg, how high does the ball go? acceleration due to gravity is g = 9.8 m/s^2. a. 22.5 m b. 20.0 m c. 25.0 m d. 17.5 m

You and a friend (alex) are at a a tree-top adventure park .. . part of the course requires you to climb up a rope. you both climb the same rope in the same amount of time. however, the tension in the rope is greater when alex climbs. who did the most work? alex did - more tension means more force - more force means more work was done you did - less tension means less force - less force means more work was done to find the work done, the force exerted and distance moved are multiplied. a couch is moved twice before you are happy with its placement. the same force was used to move the couch both times. if more work is done the first time it is moved, what do you know about the distance it was moved? when more work was done, the couch was moved less. when more work was done, the couch was moved further. when more work was done, the couch wasn't moved at all. when more work was done, the couch was moved the same distance.

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?