a machine whose velocity ratio is 4 has 75% efficiency. calculate the effort required to lift a load of 1800N​

Which configuration would produce an electric current? a) rotate a coil of copper wire between two magnets. b) connect a wire between a copper and zinc strip sitting in a beaker of water. c) connect a wire to the (+) positive end of a battery and the other end to a light bulb. d) connect a wire to the negative end of a battery and the other end to a light bulb.

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

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