# Mental block questions

1. Sep 28, 2005

### venium

mental block questions!!!

Something about these questions got me, maybe im looking for some complex answer when its more simple then i think.

1.A 20.0 Kg toboggan is pulled along by a force of 30.0N
a)what is the force of gravity on the toboggan?
b)What is the coefficient of friction?
c)How much force is needed to pull the toboggan if two 60.0 Kg girls are sitting on it?

2. A book has a mass of 400 g. When you slided the book against the floor with 5 N, it accelerated at the rate of -1.5 m/s2. What would the coefficient of friction between the book and the floor be?

3. Vancouver and Coquitlam are 30.0km apart. Car A drives from Vancouver to Coquitlam at a constent velocity of 20km/h. Car B drives from Coquitlam to Vancouver at a constent velocity of 35km/h. How much time will pass before Car A and Car B cross paths?

I know the answers to these questions because there in my book, but i dont know how to get these answers. Can you show me what formulas to use and the steps to get the answers? thanks.

2. Sep 28, 2005

### zwtipp05

Show us what you tried and we'll try to help you out and show you where you went wrong.

Some things to know.

mu*N=Force of friction

x=v*t