engineering
posted by sarah .
a boy of mass 40kg is sliding down the spiral slide at a constant speed such that his position is measured by
theta=(0.7t) rad
and
z=(0.5t) m
where t is in seconds. How do you find the components of forces Fr, Ftheta and Fz which the slide exerts on the boy at the instant when t=2s. Neglect the size of the boy.

I need to know r
w = d theta/dt = .7
Fr = 40 r w^2 = 40 r (.49) inward (negative r direction)
the tan of angle of the slide down from horizontal = .5/(wr) = .5/(.7r) = .714/r
Fz = weight of boy up = 40*9.8 = 392 N
Ftheta = weight tan angle = 392 (.714/r)