Two dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. The block has a mass m=10kg and is being pulled by a force F on a table with coefficient of static friction μs=0.3. Four forces act on it: The applied force F (directed θ=30∘ above the horizontal). The force of gravity Fg=mg (directly down, where g=9.8m/s2). The normal force N (directly up). The force of static friction fs (directly left, opposing any potential motion). If we want to find the size of the force necessary to just barely overcome static friction (in which case fs=μsN), we use the condition that the sum of the forces in both directions must be 0. Using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as:   Fcosθ−μsN=0   Fsinθ+N−mg=0 In order to find the magnitude of force F, we have to solve a system of two equations with both F and the normal force N unknown. Use the methods we have learned to find an expression for F in terms of m, g, θ, and μs (no N).  find the magnitude of the force F (in kg⋅m/s2) necessary to make the block move.

University Physics Volume 1
18th Edition
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:William Moebs, Samuel J. Ling, Jeff Sanny
Chapter2: Vectors
Section: Chapter Questions
Problem 26P: In a tug-of-war game on one campus, 15 students pull on a rope at both ends in an effort to displace...
icon
Related questions
Question

Two dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. The block has a mass m=10kg and is being pulled by a force F on a table with coefficient of static friction μs=0.3. Four forces act on it:

  • The applied force F (directed θ=30∘ above the horizontal).
  • The force of gravity Fg=mg (directly down, where g=9.8m/s2).
  • The normal force N (directly up).
  • The force of static friction fs (directly left, opposing any potential motion).

If we want to find the size of the force necessary to just barely overcome static friction (in which case fs=μsN), we use the condition that the sum of the forces in both directions must be 0. Using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: 

  •  Fcosθ−μsN=0 
  •  Fsinθ+N−mg=0

In order to find the magnitude of force F, we have to solve a system of two equations with both F and the normal force N unknown. Use the methods we have learned to find an expression for F in terms of m, g, θ, and μs (no N).

 find the magnitude of the force F (in kg⋅m/s2) necessary to make the block move.

Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 2 images

Blurred answer
Knowledge Booster
Length contraction and Lorentz equation
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
University Physics Volume 1
University Physics Volume 1
Physics
ISBN:
9781938168277
Author:
William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:
OpenStax - Rice University