An object's two dimensional velocity is given by v(t) = ( tsin(pi/3t) , 2cos(pi/2t )- t ). What is the object's rate and direction of acceleration at t=8 ?

1 Answer
Jun 1, 2017

The rate of acceleration is =1.71ms^-2 in the direction 35.7º clockwise from the x-axis.

Explanation:

The acceleration is the derivative of the velocity.

v(t)=(tsin(1/3pit), 2cos(1/2pit)-t)

a(t)=v'(t)=(1*sin(1/3pit)+t*1/3picos(1/3pit), -2*1/2pisin(1/2pit)-1)

=(sin(1/3pit)+1/3pitcos(1/3pit),-pisin(1/2pit)-1)

Therefore,

a(8)=(sin(8/3pi)+8/3picos(8/3pi),-pisin(4pi)-1)

=(1.39,-1)

The rate of acceleration is

||a(8)||=sqrt(1.39^2+1^2)

=sqrt(2.93)

=1.71ms^-2

The direction is

theta=arctan(-1/1.39)=-35.7º