Which piece of evidence would prove that a reaction is exothermic?
there is a phase change during the reaction.
one of the reactants is baking soda.
the reactants have more energy than the products.
there are more moles of gas in the products than in the reactants.

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?

An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.13 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.04 rev/s. (a) which rate of rotation gives the greater speed for the ball? 6.04 rev/s 8.13 rev/s (b) what is the centripetal acceleration of the ball at 8.13 rev/s? m/s2 (c) what is the centripetal acceleration at 6.04 rev/s? m/s2

When barack obama was running for president, at a campaign stop he tried to bowl, something he isn't very good at. the media loved it because he threw a gutter ball while they were all watching. this is an example of: