- #1
Jrlinton
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- 1
Homework Statement
A 0.25 kg particle moves in an xy plane according to x(t) = -15 + 2t - 4t3 and y(t) = 25 + 7t - 9t2, with x and y in meters and t in seconds. Find formulas at time t<35 sec for the (a) the magnitude and (b) the angle (relative to the positive direction of the x axis) of the net force on the particle (in radians), as well as (c) the angle of the particle's direction of travel (in radians)
Homework Equations
F=ma
Pythagorean thereom
Fx=Fcosθ
Fy=Fsinθ
The Attempt at a Solution
With the x(t) and y(t) being the decoupled position vector, I thought I would use Pythagorean Thereom to come up with the vector r
r=((-4t^3+2t-15)^2+(-9t^2+7t+25)^2)^0.5
r=(16t^6+65t^4-6t^3-397t^2+290t+850)^.5
approximating the square roots for the coeffecients:
r=4t^3+9.06t^2-2.45t^1.5-19.92t+17.03t^0.5+29.15
I have a strong suspicion that I went about this in a very wrong way