Question

A block of mass m = 4.0kg is at rest on a horizontal frictionless floor. At time t = 0 a horizontal force F = F xt is applied to the block. At an instant of t later the block is at x = 2.0t4 (x is in meters) from the block's initial position, x = 0. 1. Find F x, the x-component of the force F as function of time. (3 pts) Fx (t) = 2. Find the instantaneous power created by force F as function of time. (3 pts) P(t) =

Answer 1

mo 1. 1 Given n = 4.0 kg F = Fx X = 2.0+* Diffrentiating equatioii @.w.x.t t, we get da = 2.034 t 80t² > v= 8.0 +² ③ cagain differentiating above equation, we get arx = 80x3 t² = 24.0 +2 de a = 2400 t² ©[: 2 dt 이t2 ca acceleratori at NOW, F = m The the = MOX 24.042 F.667= 96.04? Instantaneous power is given by Pet)= F(t). Plt) = 96.0t'x 80+3 = 768.0 +5 5 Plt) = 768 t