/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 4 In cross-country skiing, skis sh... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 5: Problem 4

In cross-country skiing, skis should easily glide forward but should remain at rest when the skier pushes back against the snow. What frictional properties should the ski wax have to achieve this goal?

Short Answer

Expert verified
The ski wax needs high kinetic friction to allow the skis to easily glide forward. As for the backward motion resistance, it should posses high static friction. Thus, the ski wax should have properties that reduce kinetic friction and increase static friction.

Step by step solution

01

Understanding Friction

Friction is a force that opposes motion between two surfaces that are in contact. Kinetic friction (also called sliding or dynamic friction) occurs when two objects are in motion relative to each other, it's less than the static friction. Static friction comes into play when an object is stationary; it needs to be overcome for the object to start moving.
02

Applying Theory to the Exercise

Skiing involves two main motions - moving forward (gliding) and pushing backwards. For smoother gliding or moving forward, the skis need to have a high kinetic friction. This means the wax applied must decrease the friction between the ski and the snow to allow easy forward motion. Conversely, while pushing back against the snow, the skis should remain at rest. This implies that a high static friction is required; the ski wax should increase the friction to prevent or resist the backward movement.
03

Conclusion

The ski wax should have properties that reduce kinetic friction for a smooth forward glide and increase static friction to provide resistance against a backward push.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A block is launched with speed \(v_{0}\) up a slope making an angle \(\theta\) with the horizontal; the coefficient of kinetic friction is \(\mu_{\mathrm{k}}\) (a) Find an expression for the distance \(d\) the block travels along the slope. (b) Use calculus to determine the angle that minimizes \(d\).

A 2.1 -kg mass is connected to a spring with spring constant \(k=150 \mathrm{N} / \mathrm{m}\) and unstretched length \(18 \mathrm{cm} .\) The two are mounted on a frictionless air table, with the free end of the spring attached to a frictionless pivot. The mass is set into circular motion at \(1.4 \mathrm{m} / \mathrm{s} .\) Find the radius of its path.

At the end of a factory production line, boxes start from rest and slide down a \(30^{\circ}\) ramp 5.4 m long. If the slide can take no more than \(3.3 \mathrm{s}\), what's the maximum allowed frictional coefficient?

Two blocks rest on slopes of unequal angles, connected by a rope passing over a pulley (Fig. 5.30). If the blocks have equal masses, will they remain at rest? Why? Neglect friction.

A police officer investigating an accident estimates that a moving car hit a stationary car at \(25 \mathrm{km} / \mathrm{h}\). Before the collision, the car left 47 -m-long skid marks as it braked. The officer determines that the coefficient of kinetic friction was \(0.71 .\) What was the initial speed of the moving car?
See all solutions

Recommended explanations on Physics Textbooks

Circular Motion and Gravitation

Read Explanation

Physical Quantities And Units

Read Explanation

Atoms and Radioactivity

Read Explanation

Conservation of Energy and Momentum

Read Explanation

Scientific Method Physics

Read Explanation

Thermodynamics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.