Apulley system has an efficiency of 74.2%. if you perform 200 j of work, how much useful work does the pulley perform?
a.200 j
b.148 j
c.52 j
d.113 j

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.1 m below the tank bottom which is a = 7.4 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute)

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

Acar travels in reverse. it covers 150 meters in 12 seconds what is the velocity of the car what is the speed of the car