5.Force&Motion_II

# Road surface may be enough to prevent sliding when

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Unformatted text preview: then essential. 1. What is his acceleration? 2. What force does Earth exert on Igor? A car of mass m moves at a constant speed v of 20m/s around a banked circular track of radius R=190m. If the frictional force from the track is negligible, what bank angle θ prevents sliding. The The Department of Physics, CUHK The Department of Physics, CUHK 17 18 3 §6. Review & Summary Review & Summary Drag force: when there is a relative motion between air and a body, the body experiences a drag force. Friction: when a force tends to slide a body along a surface, a frictional force from the surface acts on the body. 1. 2. D = 1 C ρ Av 2 2 If the body does not move, then the static frictional force fs and the component of F which is parallel to the surface are equal in magnitude and opposite in direction. The magnitude of fs has a maximum f s , max = µ s FN 3. Terminal speed µ s coefficient of static friction 1 2 If the body begins to slide along the surface, the magnitude of fk is f k , max = µ k FN C ρ Av 2 − Fg = 0 t vt = 2 Fg C ρA µk coefficient of kenetic friction The Department of Physics, CUHK The Department of Physics, CUHK 19 20 Review & Summary Uniform circular motion: if a particle moves in a circle at constant speed, the particle is said to be in uniform circular motion. a= v2 R F =m v2 R The Department of Physics, CUHK 21 4...
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## This document was uploaded on 09/16/2013.

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