The position of an object moving along a line is given by p(t) = sin(2t- pi /4) +2 . What is the speed of the object at t = pi/2 ?

1 Answer
Apr 29, 2016

v(pi/2)=-sqrt2

Explanation:

if p=f(t);

v=d/(d t) f(t)

v=d/(d t) (sin(2t-pi/4)+2)

v(t)=2*cos(2t-pi/4)

"for :"t=pi/2

v(pi/2)=2*cos(2*pi/2-pi/4)

v(pi/2)=2*cos(pi-pi/4)

v(pi/2)=2*cos((3pi)/4)

cos( (3pi)/4)=-cos (pi/4)=-sqrt2/2

v(pi/2)=-2*sqrt2/2

v(pi/2)=-sqrt2