Hockey Puck and Kinetic Friction

Lesson PreviewLesson Topic GraphGraph

Unit: Force and Newton's Laws

Prerequisites

Kinetic Friction

Later Topics

None

Multi-Step Problem Preview

Part 1 of 6 — sign up to solve the full problem!

Start free trial

Part 1

A hockey puck slides across a horizontal ice surface with an initial speed $v_0 = 47\,\mathrm{m/s}$ to the right and comes to rest after traveling a distance $d = 129.41\,\mathrm{m}$ . Let's find the coefficient of kinetic friction between the puck and ice ( $\mu_k$ ) with this information.

Select the correct free-body diagram for the hockey puck while it is sliding on the ice.

Correct!

Solution:

Solution

The hockey puck slides on a horizontal ice surface and experiences three forces:

Gravitational force $\vec{F}_g$ acts downward (toward the ice).
Normal force $\vec{N}$ acts upward (perpendicular to the ice surface), exerted by the ice on the puck.
Kinetic friction force $\vec{f}_k$ acts horizontally opposite to the direction of motion (opposing the velocity), causing the puck to decelerate.

Since the puck moves horizontally on a flat surface with no vertical acceleration, the normal force and gravitational force are equal in magnitude and opposite in direction. The only unbalanced force is the kinetic friction force, which points opposite to the direction of motion (backward if the puck moves forward).

The correct free-body diagram shows:

$\vec{F}_g$ pointing downward
$\vec{N}$ pointing upward (equal magnitude to $\vec{F}_g$ )
$\vec{f}_k$ pointing horizontally opposite to the velocity (causing deceleration)

Loading visualization…

Want to solve all 6 parts?

Ready to Start Learning?

Explore More Topics Try PhysicsGraph for free