A car has an engine which delivers a constant power. It accelerates from rest at time t = 0, and at t = t0 its acceleration is a0. What is its acceleration at t = 2t0? Ignore energy loss due to friction.

Question

anonymous · Answer

constant power meaning, constant force acting .. so i guess acceleration remains unchanged?!

anonymous · Answer

.nope. got the answer :)
P = FV = ma*at = ma^2 t .
therefore m(a0)^2t = m(x)^2 (2t)
solve for x which is the acceleration at 2t. 
answer is a0/sqrt(2). mission achieved :)

intuitively, acceleration needs to be negative, else the engine would go one forever.

anonymous · Answer

go on accelerating forever that is. it needs to reach a "carrying capacity"

anonymous · Answer

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so u are right