The position vector of a particle of mass 3 kg moving along a space curve is given by (r = (4t^{3} – t^{2})i – (2t^{2} – t)j) at any time t seconds. Find the force acting on it at t = 2 seconds.
Explanation
(r = (4t^{3} – t^{2})i – (2t^{2} – t)j)
(v = frac{mathrm d r}{mathrm d t} = (12t^{2} – 2t)i – (4t – 1)j)
(a = frac{mathrm d v}{mathrm d t} = (24t – 2)i – 4j)
(t = 2 : a = (24(2) – 2)i – 4j)
(a = 46i – 4j)
(F = ma = 3(46i – 4j))
= (138i – 12j)N)