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xr250h

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**Block and cart friction problem - SOLVED**

## Homework Statement

You and your best pal make a friendly bet that you can place a 2.0-kg box against the side of a cart, and that the box will not fall to the ground, even though you guarantee to use no hooks, ropes, fasteners, magnets, glues, or adhesives of any kind. When your friend accepts the bet, you begin pushing the cart. The coefficient of static friction between the box and the cart is .60.

a.) Find the minimum acceleration for which you will win the bet.

b.)What is the magnitude of the frictional force in this case?

c.) Find the force of friction on the box if the acceleration is twice the minimum needed for the box to not fall

d.) Show that, for a box of any mass, the box will not fall if the magnitude of the forward acceleration is [tex]a \geq g/\mu[/tex] where [tex]\mu[/tex] is the coefficient of static friction.

## Homework Equations

[tex]F = ma[/tex]

## The Attempt at a Solution

I'm not really sure where to start with this one. I set up a Fnetx and Fnety equation but I don't know how to relate the two.

Fnetx = Fa = m*ax where Fa = force applied

Fnety = Ff - Fg = m*ay = 0 (if the block isn't sliding down)

I don't really know where to go from here.

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