Asked by john

A student wants to determine the coefficients of static friction and kinetic friction between a box and a plank. She places the box on the plank and gradually raises one end of the plank. When the angle of inclination with the horizontal reaches 30°, the box starts to slip, and it slides 2.4 m down the plank in 3.6 s at constant acceleration.
(a) What is the coefficient of static friction?


(b) What is the coefficient of kinetic friction?

Answered by drwls
a) tan 30
b) write the equation of motion, with a retarding force proportional to the kinetic friction coefficient, Uk. Compute the acceleration from the fact it takes 3.6 s to make it down the plank, starting at zero velocity. Solve for Uk
Answered by john
During an Olympic bobsled run, the Jamaican team makes a turn of radius 7.6 m at a speed of 97.2 km/h. What is their accelaration in g?
There are no AI answers yet. The ability to request AI answers is coming soon!