Question

The position of an object moving along a line is given by `p(t) = 4t - sin(( pi )/4t)`. What is the speed of the object at `t = 9`?

Answer 1

The speed is `=3.44ms^-1`

Explanation:

The velocity is the derivative of the position.

`p(t)=4t-sin(pi/4t)`

`v(t)=p'(t)=4-(pi/4)cos(pi/4t)`

Therefore,

`v(9)=4-(pi/4)cos(pi/4*9)=3.44ms^-1`