Explain why adding oil to the moving parts of a machine can increase its efficiency

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

How many meters will a car travel if its speed is 45 m/s in an interval of 11 seconds? question 2 options: a) 450 meters b) 495 meters c) 4.09 meters d) 498 meters