English Deutsch Français Italiano Español Português 繁體中文 Bahasa Indonesia Tiếng Việt ภาษาไทย
All categories

A cyclist is coasting at a steady speed of 12m/s but enters a muddy stretch where the effective coefficient of friction is .60. Will the cyclist emerge from the muddy stretch without having to pedal if the mud last for 11m? If so, what will be the speed upon emerging?

2006-10-26 23:09:35 · 4 answers · asked by Anonymous in Science & Mathematics Physics

4 answers

I know how the methods o resolve ta ht problems because I study Engineering, but can you tell me the problem or at least the variables in Spanish?

Thanks.

2006-10-26 23:20:03 · answer #1 · answered by Yerman 2 · 0 0

This problem is similar to the one concerning those police investigators. It's about kinetic energy, work energy, kinetic friction, and conservation of energy.

Let's go through the solution, and you'll see the similarity:

KE=1/2mv^2=1/2m*12^2=72m Joules
f=uR=0.8mg
Work=f*s=0.8mg*11
=0.8m*9.8*11=86.24m Joules

You will note that the KE was not enough to overcome
the work needed, i.e. 72m J<86.24m J

So he has to pedal at a speed of x to do so. Let's write the equation involving conservation of energy:

KE initial + KE additional=86.24m
72m+1/2mx^2=86.24m (m cancels out)
1/2x^2=86.24-72
x^2=2*14.24
=28.48
x=5.34m/s

2006-10-27 02:39:25 · answer #2 · answered by tul b 3 · 0 0

If the cyclist doesn't pedal he will will probably have a speed reduction to about 5.4m/s. He won't fall over but he will have to pedal if he is to regain his speed, this is assuming he's traveling on a level surface& there is no wind resistance.to get more exact you'll also have to concider the affects of gravity as well.

2006-10-26 23:36:01 · answer #3 · answered by Ellen 3 · 0 0

i am sorry, but it is always better to ask your physics teacher...he knows a lot more than I do...

2006-10-26 23:13:18 · answer #4 · answered by olivettiz 2 · 0 0

fedest.com, questions and answers