Re: Calculate force given power

On Apr 14, 8:04 pm, DavidBrown...@xxxxxxxxx wrote:
I need to describe the motion (acceleration, velocity, time) of a
vehicle moving on a surface that may or may not be inclined, taking
into account rolling resistance and air drag, including wind.  That
would be easy enough if I had a force, but I only have the power input
and mass.  I know P = F · v, but the vehicle starts at rest, and
division by 0 doesn't work well.  Anybody have any clue how I can go
about solving this.

Supposing you can ignore friction and wind and such, you've got

Energy = 1/2 m v^2

and supposing that you are accelerating in one direction starting
from rest, then you've got that the energy is just proportional to
time.

1/2 m v^2 = P t

or

v = sqrt(2 P t / m)

and a time deriv will give a gnarly acceleration at t=0, but
no problem in velocity or position.
Socks
.

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