Answer:
Graph D
Explanation:
The speed of sound in steel or any solid is faster than the speed of sound through air. This means the steel bar on the graph graph should be the larger of the two.
Answer:
A negative slope results when an individual is moving away
Explanation:
Lubricating a machine will make it more efficient and it will reduce the friction between the parts meaning that less energy will be transferred and dissipated into the surroundings as heat.
the in put and out put force may increase as it's easier for the machine to work due to less friction