# Homework Help: 2 force practice problems

1. Nov 18, 2009

### reddeffect

an elevator weighing 2x10^5n supported by a cable what is the tension on the cable when accelerating up is 3m/s2 g=9.8 obviously

and

an ice skater moves at 10 m/s and coasts to a halt in 100 meters on smooth ice what is the coefficient of friction on skates/ice

i have tried many different ways and am not coming up with the answer i was given any help is greatly appreciated.

2. Nov 18, 2009

### Jack21222

It might be worthwhile to post some of the "many different ways" you've attempted, as per the template which you deleted when you posted.

3. Nov 19, 2009

### donhubix

Question A-elevator)

Forces pointing downwards: Weight of lift
Forces pointing upwards: Tension force, ma(where m and a are mass and acceleration of lift respectivelly)

Balance the two equations to find the missing link: The tension force.

QuestionB-ice skater)

Do exactly the same:

From the data given (v and s) you can find the acceletarion(or rather deceleration), from this the coefficient of friction can be found easily.