An object's velocity is given by v(t) = (2t^2 -t +2 , sint ). What is the object's rate and direction of acceleration at t=4 ?

1 Answer
May 6, 2017

The rate of acceleration is =15.01ms^-2 in the direction of =177.5º

Explanation:

The acceleration is the derivative of the velocity.

v(t)=(2t^2-t+2,sint)

a(t)=v'(t)=(4t-1,cost)

Therefore,

a(4)=(15,cos4)=(15,-0.65)

The rate of acceleration is

||a(4)||=sqrt(15^2+(0.65)^2)

=sqrt225.4

=15.01ms^-2

The direction is

theta=arctan(-0.65/15)

theta lies in the 2nd quadrant

theta=180-2.5=177.5º