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:
It will go about 45-50 mph.
Explanation:
Depending on what you are hauling.
Think of the formula force=mass x acceleration. even though they have the same acceleration, a train has more mass. is that helpful?
Answer:
1. False
2. True
3. True
Explanation:
1- False —> The relation between electric potential and electric field is given such that

Therefore, for a uniform E field, electric potential is linearly proportional to the distance.
2- True —> The electric field lines always cross the equipotential lines perpendicularly.
3- True —> In order to be a potential difference, one source of electric field is enough. The electric potential will decrease radially according to the following formula:

There is no test charge in the formula, only the source charge. Even when there is no test charge, the potential difference between points in space can exist.