Which sentences describe star clusters? Check all that apply. Stars appear brighter. Stars form large groupings. Stars form at different times. Stars form from the same nebula. Stars are about the same distance from Earth.

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied.

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final