Ahmed is a heating consultant. One of his clients has a boiler that is 62% efficient and uses heating oil that releases 4.15 x 107 J kg-1 of heat energy when it bums in air. What mass of heating oil does the boiler need to heat 245 kg of water from 12.0 °C to 68.0 °C?

Magma  is composed of molten rock and is  stored  in the earth's crust. lava is  magma  that reaches the surface of our planet through a volcano vent.

I'm having some difficulty seeing the diagram clearly.but the question says there's a net inward force on the object.so we know right away,  from newton's 2nd law of motion, thatthat baby is accelerating.  it doesn't even matter which way thenet force is pointing.  if there's any net force, then either theobject's speed or else its direction must be changing.