Forces On An Inclined Plane. F N. Think about the forces as she sleds down the hill in the laundry basket (if it is not a non-frictionless surface). Can you label them? . F f. 30°. What is the formula used to calculate F g ?. F g. = mg. How many other forces are there? (Don’t make any up!).
Think about the forces as she sleds down the hill in the laundry basket (if it is not a non-frictionless surface). Can you label them?
What is the formula used to calculate Fg?
How many other forces are there? (Don’t make any up!)
Two; the normal force (FN) and the force of friction (Ff).
= Fgsin θ
The formulas used to calculate the components are:
= Fgcos θ
One way to remember when to use cosine or sine is to look at the formulas on your reference table. Ax = A cos θ (horizontal) and Ay = A sin θ (vertical). Just use the opposite function for that direction when on an incline. Fg┴ = Fgcos θ (vertical) and Fgll = Fgsin θ(horizontal).
of the forces in the x- direction)
If a 60 kg person is sledding down a hill on waxed skis (yes, it’s a laundry basket, but just pretend!) at a 30o incline at a constant velocity, calculate Fnet, FN, Fgll, Fg┴ , Fg, and Ff.
The easiest thing to find first is the weight (Fg).
Use the weight to find it’s vectors.
Fg┴ = Fgcos θ
Fgll = Fgsin θ
Fgll = (588.6N)sin(30°)
Fgll = (588.6N)(0.500)
Fgll = 294.3N
Fg┴ = (588.6N)cos(30°)
Fg┴ = (588.6N)(0.866)
Fg┴ = 509.73N
It is equal to Fg┴. The normal force is pushing down with 509.73N of force while the ground is pushing up with an equal amount of force.
FN = 509.73N
To find the force of friction, plug in the normal force and the coefficient of friction that says waxed ski on snow.
This would be ________ friction because it is SLIDING.
Ff = μFN
*Since coefficients of friction don’t have units, keep the unit of a Newton.*
Ff = (0.05)(509.73N)
Ff = 25.49N
Since she is going down the hill at a constant velocity, what does that mean?
Ff = 25.49N
Keep that in mind!
ΣFx = Fnet = ma = Fgll – Ff
Fnet = Fgll– Ff
Subtract the force of friction because it is in the opposite direction of motion.
Fnet = 294.3N – 25.49N