Attempt 2 - Incorrect - 4.50 sBlock on Incline: Calculate μk &Travel Time

[mparsons06]

Homework Statement

A cube of mass M=0.425 kg is placed on an incline of 12.5* and given a push. It slides down, and its speed down the incline is measured at two positions, [1] and [2] on the diagram below, with V1 = 0.913 m/s and V2 = 1.171 m/s. Note that the incline passes through at least two grid intersections and that one cube corner is at x grid lines. (See attachment.)


A. Calculate μk, the coefficient of kinetic friction for the block on the incline.


B. Calculate the travel time of the cube from position 1 to position 2.



2. The attempt at a solution

A. Attempt 1 - Incorrect - 0.813
Attempt 1 - Incorrect - 0.2216
Attempt 1 - Incorrect - 0.222

B. Attempt 1 - Incorrect - 2.67 s

 

[aim1732]

What is the problem? Just calculate the acceleration down the incline with a supposed coefficient of friction. Then use kinematic eqns. to make out the coefficient.