Coefficient of static friction and minimum horizontal force

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SUMMARY

The minimum horizontal force required to hold a 5.0 kg mass against a wall with a coefficient of static friction of 0.85 is 58 N. The calculation involves using the formula for frictional force (Ff = μFn), where Ff must equal the weight of the mass (approximately 49 N). The misunderstanding arose from not correctly identifying the normal force (Fn) in the equation, which is essential for determining the correct frictional force needed to counteract the weight.

PREREQUISITES
  • Understanding of static friction and its coefficient
  • Knowledge of Newton's second law of motion
  • Ability to calculate weight using mass and gravitational acceleration
  • Familiarity with basic algebra for solving equations
NEXT STEPS
  • Review the concept of normal force in physics
  • Study the relationship between frictional force and applied force
  • Learn about different coefficients of friction for various materials
  • Practice problems involving static friction and inclined planes
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and forces, as well as educators looking to clarify concepts related to static friction and force calculations.

kamalpreet122
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Homework Statement



A 5.0 kg mass is held against a wall with which it has a coefficient of static friction of 0.85. What is the minimum horizontal force required to hold the mass against the wall ?

The teacher said answer is 58 N .. i can't get to that answer..

Homework Equations



Ff = UFn

The Attempt at a Solution



Ff = 0.85(49)
Ff = 41.65

this answer makes sense but for some reason ..the teacher has given us a different answer :S
 
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Fnis the unknown.

Ff must be equal to the weight.
 


yea that makes a lot of sense thanxx a lot :D
 

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