Answer:
C Don't worry if you thought it was D. I almost answered that.
Explanation:
Remark
You can get this just by learning the vocabulary.
Efficiency = Work Out / Work In * 100%
Work in = 30J That's you swinging the hammer.
Work out = 10 J That's how much of the hammer's work gets to the nail.
Efficiency = (10/30)*100
Efficiency = 1/3 * 100
Efficiency = 33%
<span>
Total distance covered = 40+20+30 = 90 km
Total time taken to cover this distance = .5 hr + .2 hr + .75 hr = 1.75 hr
Avg. speed of Trip would be
90/1.45 = 62.07 km</span>
What the question for this assessment
As a ball rolls ... even if there were no air resistance ... the ball
has to push down and climb over every one of those little fibers
that stick up from the felt fabric on the table. As it does that, each
little fiber brushes against the ball, and robs a tiny tiny bit of its
kinetic energy.
