Question

A rabit run accross a parking lot on whicha a set of cordinate axes has strangely enough been drawn the cordinates of the rabits's as function of time t are given by
x = -0.31t2 + 7 .2t + 28
Y= 0.22t2 - 9.1t + 30
At = 15 s what is the rabbit's position vector r in umivector notation and in magnitude angle notation?

Answer 1

Given:

$x(t)=-0.31t^2+7.2t+28\\ y(t)=0.22t^2-9.1t+30$

At $t=15 \:\rm s$

$$x(15)=66\:{\rm m}\\ y(15)=-57\:{\rm m}\\$$

$${\bf r}=66{\bf \hat i}-57{\bf\hat j}\\ {\bf r}=(87,-41^{\circ})$$