Question

a particle is moving in a straight line. its displacement at time t is given by=-4t^2+ 2t, then its velocity and acceleration at time t=1/2 second are

a) -2, -8

b)2,6

c)-2,8

d) 2,8

Answer 1

$$\begin{gathered} s=-4t^2+2t \\ velocityv=\frac{ds}{st}=-8t+2 \\ accelerationa=\frac{dv}{dt}=-8m/s^2 \\ attimet=\frac{1}{2}sec \\ velocityv=-8\left(\frac{1}{2}\right)+2=-2m/s \\ accelerationa=-8m/s^2 \\ ansis\left(a\right) \end{gathered}$$