I am unsure about this question, could you please help me:
INFO: The power to weight ratio of an engine is defined to be the max power an engine can produce divided by the mass of the engine.
A certain jet engine has a mass of 4000kg and a power to weight ratio of 12000Js-1kg-1 . An aeroplane of unloaded weight of 140 tonnes contains two of these engines.
1) What the overall power to weight ratio?
2) Neglecting friction, how long would it take for the plane to accelerate from 0 to 60 mph? How long to accelerate 120 to 180? 180 to 240?
Wouldn't the overall power to weight ratio be 12000* 2 (Jet engines) ?
for no.2 do you use P=W/t and W= change in Ke ?
...for the 2nd time this year