The position of an object moving along a line is given by p(t) = 2t - tsin(( pi )/8t) . What is the speed of the object at t = 3 ?

1 Answer
Apr 28, 2017

The speed is =0.63ms^-1

Explanation:

We need

(uv)'=u'v+uv'

The speed is the derivative of the position

p(t)=2t-tsin(pi/8t)

Therefore,

v(t)=2-(sin(pi/8t)+t*pi/8cos(pi/8t))

=2-sin(pi/8t)-(tpi)/8cos(pi/8t)

When t=3

v(3)=2-sin(3/8pi)-(3/8pi)cos(3/8pi)

=2-0.92-0.45

=0.63ms^-1