# Math and Physics

• January 23rd 2008, 06:40 PM
ffezz
Math and Physics
Hi Everyone.

Straight to the problem

A skier on a slope inclined at 4.7 degrees to the horizontal pushes on ski poles and starts down the slope. The initial speed is 2.7m/s. The coefficient of kinetic friction between skis and snow is 0.11. Determine how far the skier will slide before coming to rest.

In between steps appreciated.

Thanks,
Chris
• January 23rd 2008, 08:55 PM
Singular
How much did the skier wheigh?
• January 23rd 2008, 09:10 PM
JaneBennet
Let m be the skier’s mass, R the normal reaction of the slope on him and a his acceleration down the slope.

Resolving perpendicular to the slope surface: $R=mg\cos{4.7^\circ}$

Resolving parallel to the slope surface: $ma=mg\sin{4.7^\circ}-0.11R=mg\sin{4.7^\circ}-0.11mg\cos{4.7^\circ}$

$\therefore\ a=g\sin{4.7^\circ}-0.11g\cos{4.7^\circ}$

Note that a will be negative.

Now use $v^2=u^2+2as$ to find s.