# Friction and force problem.

-Dragoon-

## Homework Statement

a) Find the net forces acting on the puck. Remember to consider both horizontal and vertical forces.
b) If the puck leaves the stick with a velocity of 45m/s, how far will the puck travel in 3 seconds?

## Homework Equations

Fnet (horizontal) = fapplied + forced friction
Fnet (vertical) = f gravity + f normal
Δd = (horizontal distance traveled) x (change in time)
c^2 = a^2 +b^2
f = (mass) x (acceleration)

## The Attempt at a Solution

For a, I start with finding the horizontal net force by using the first equation. After adding both the frictional force and applied force, I yield 16.05 N. Then I find the force of gravity by using the last equation (0.164 kg)(9.8m/s^2) and yields a value of 1.568 N. I know the magnitude of the force of gravity is equal to force normal, so that would also be 1.568 N. Now I use the second equation to find the vertical net force, which yields 3.136 N. Now that the net-forces are perpendicular, I use pythagorean theorem to find the resultant which yields 16.4 (√(3.316N)^2 + (16.05 N)^2) and finally yielded a value of 16.4 N as the total net force that is acting on the puck. Is this correct? I may have wrongly assumed that, there is a vertical net force due to the question asking to consider both vertical and horizontal forces and I haven't solved a question with a vertical net force in the lesson as of yet.

For b, I actually have no idea how to solve, seeing as I haven't even seen a question like this in the lesson nor are there any examples. I assume we use the third equation which would then yield a value 135 m.

Staff Emeritus
Homework Helper

## Homework Statement

a) Find the net forces acting on the puck. Remember to consider both horizontal and vertical forces.
b) If the puck leaves the stick with a velocity of 45m/s, how far will the puck travel in 3 seconds?
It looks like you have left out part of the problem statement.

## Homework Equations

Fnet (horizontal) = fapplied + forced friction
Fnet (vertical) = f gravity + f normal
Δd = (horizontal distance traveled) x (change in time)
c^2 = a^2 +b^2
f = (mass) x (acceleration)

## The Attempt at a Solution

For a, I start with finding the horizontal net force by using the first equation. After adding both the frictional force and applied force, I yield 16.05 N. Then I find the force of gravity by using the last equation (0.164 kg)(9.8m/s^2) and yields a value of 1.568 N. I know the magnitude of the force of gravity is equal to force normal, so that would also be 1.568 N. Now I use the second equation to find the vertical net force, which yields 3.136 N.
Is that 3.136 N vertical force in the upward or downward direction? Assuming you have the correct magnitude for the normal and gravity forces, do you know in which direction each of those forces acts? Did you account for those directions when you added those two vectors?

Now that the net-forces are perpendicular, I use pythagorean theorem to find the resultant which yields 16.4 (√(3.316N)^2 + (16.05 N)^2) and finally yielded a value of 16.4 N as the total net force that is acting on the puck. Is this correct? I may have wrongly assumed that, there is a vertical net force due to the question asking to consider both vertical and horizontal forces and I haven't solved a question with a vertical net force in the lesson as of yet.

For b, I actually have no idea how to solve, seeing as I haven't even seen a question like this in the lesson nor are there any examples. I assume we use the third equation which would then yield a value 135 m.