Do you think the mass of an object greatly affects the coefficient of friction?

At what time will the interfering waves have an amplitudeof zero?

As you lift an 88 n box straight upward you produce a power of 72 w. what is the speed of the box?

In a particular chemical reaction, the energy of the reactants is 30 kj and the energy of the products is 5 kj. 
 the maximum energy of the system is 40 kj. sketch a potential energy diagram for this reaction. make sure to label the energy of the reactants, the energy of the products, the activation energy, and the enthalpy change for the reaction.