Answer:
Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work).
Explanation:
It is a measure of how well a machine reduces friction.
Answer:
harmful effects
1. that will cause air pollution
2. that will destroy our earth
Answer:
I don't exactly know what you learned but it could be because of more friction or the bus was running out of gas.
