A mirror has an object located on its principal axis 40.0 cm from the mirror's surface. A virtual image is formed 15.0 cm behind
the mirror. What is the mirror's focal length?
a. -240 cm
C. 2.38 cm
b. -10.9 cm
d. 13 cm

Which statements describe how a machine can make work easier? check all that apply. it can put out more force than the input force by decreasing the distance through which force is applied. it can increase the amount of work performed if the output force is in the same direction as the input force. it can apply a force to an object in a different direction than the force applied to the machine. it can increase the distance through which a force acts by exerting less force than was used on it. it can exert a greater force through a greater distance than the force used on the machine.