a 20 kg box containing books was lifted from the floor by a student to a 1 meter high table. How much work is done by the student in lifting the box?

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?

6–48 bananas are to be cooled from 24 to 138c at a rate of 215 kg/h by a refrigeration system. the power input to the refrigerator is 1.4 kw. determine the rate of cooling, in kj/ min, and the cop of the refrigerator. the specific heat of banana above freezing is 3.35 kj/kg·8c.