posted by em on .
Starting from rest, a 4.4 kg block slides 3.5 m down a rough 22.3o incline in 2.4 seconds. Determine the energy lost due to friction. (Hint: find the final kinetic energy and subtract that from the work done by gravity.)
Enter your answer here: J
Your hint tells you how to do it.
The final velocity is twice the average velocity of 3.5/2.4 m/s, which would be
Vfinal = 2.92 m/s
Energy lost = M g H - (1/2) M Vfinal^2/2
You do not need to use the slope of the incline to get the answer. You COULD use it to get the kinetic friction coefficient.
average velocity= distance/time=3.5/2.4 m/s
so final velocity= 2*averagevelociyt
and KEfinal= 1/2 m vf^2
height of ramp= 3.5sin22.3
energy from friction= mgh- KEfinal