- #1

sadpwner

- 8

- 0

## Homework Statement

A boy slides on a sled on the curved track sketched (black line). (Treat the boy and sled as a particle.) His mass plus that of the sled is

*m*= 41 kg. Friction and air resistance are negligible (I want a sled like that!). His initial speed is

*v*0 = 1.3 m.s–1. The height

*h*= 4.3 m. At the bottom, the track has a radius of curvature (grey circle)

*R*= 3.2 m. At the bottom of the track, what is the normal force exerted by the track on the sled?

## Homework Equations

ac=v^2/r

W=mg

Ui+Ki=Uf+Kf

## The Attempt at a Solution

N+Fcentripetal=W

N=W-Fc

W=mg=-9.8*41

Ui+Ki=Uf+Kf

m*g*h+m*v0^2/2 =m*v^2

2*g*h+v0^2=v^2

2*-9.8*4.3+1.3^2=-82.59

I would plug this into the centripetal acceleration formula but v^2 shouldn't be a negative number so I am not quite sure if I got the right number.