(adsbygoogle = window.adsbygoogle || []).push({}); plz plz plz plz help me with this question.

Hi every one,

i'm gettin crazy trying to solve this question, plz do help if u could, i would really appreciate that.

-------

** A crane uses its petrol engine to lift a beam of mass 1000 kg by height h. The fuel burned loses 1 MJ (million J) of chemical potential energy, 85% of this being transferred by heating to the air. The internal energy of the crane's engine increases by 4.0×10000 J, while that of the crane's superstructure and the beam is unchanged. The crane's superstructure ( not engine of fuel) increases in graviational potential energy by 10000 J. Everything is at rest before and after. Assume all transfer by working out of the crane is used to lift the beam.

(a) The calorific value of the fuel is 43 MJ/kg, its density is 737 kg m(to power -3) and it costs 90p (pens) per liter (there are 1000 liter in 1 m to power 3). What was the fuel cost of raising the beam?

(b) What is the change in total energy of the beam in terms of h?

(c) Consider the energy changes of the whole crane (fuel + engine + superstructure) to find the height h.

(d) Consider the energy changes of the engine (including fuel). If the whole process takes 55 seconds, find the average power output by working of the engine.

--------

plz help me.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Me with this question.

**Physics Forums | Science Articles, Homework Help, Discussion**