An object's two dimensional velocity is given by v(t) = ( t-2 , 2cos(pi/2t )- t )v(t)=(t2,2cos(π2t)t). What is the object's rate and direction of acceleration at t=3 t=3?

1 Answer
May 21, 2017

The rate of acceleration is =2.36ms^-2=2.36ms2 in the direction
theta=65º anticlockwise from the x-axis

Explanation:

The acceleration is the derivative of the velocity.

v(t)=(t-2, 2cos(pi/2t)-t)

a(t)=v'(t)=(1, -pisin(pi/2t)-1)

Therefore,

a(3)=(1, pi-1)=(1,2.14)

The rate of acceleration is

||a(4)||=sqrt(1+2.14^2)

=sqrt5.59

=2.36ms^-2

The direction is

theta=arctan((pi-1))

theta lies in the 1st quadrant

theta=65º anticlockwise from the x-axis