a level surface at the bottom with a speed
of 6.7 m/s. The coefficient of kinetic friction
between runners and snow is 0.048, and the
girl and sled together weigh 615 N.
The acceleration of gravity is 9.8 m/s.
How far does the sled travel on the level
surface before coming to a rest?
Answer in units of m
For this problem, I started it just like any other force problem. I set up a diagram drawing all the forces acting on the girl while going down the sled. Normal force perpendicular to the surface, Fg going downwards which is 615N, and the Ff which is mew (subscript k) times N. Mew in this instance is .048 as indicated in the question.
I believe you have to find the acceleration before you plug it into a kinematic equation. So using the equation F=ma, I decided to find mass first by using Fg= mg. Fg= 615N and g=9.8. So I did 615/9.8 to get the mass of 62.75510204.
Then would I use Ff= mew (times) N to find F in F=ma? If so, what would N=? Would it be 615?
1 comment:
You're on the right track. After multiplying mu and the reaction force of 615N you can divide that by the total mass/gravity. This gives you the rate of deceleration. You can then use the v^2=vo^2+2a(deltax) and solve that for x.
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