- #1

Hemmelig

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**[SOLVED] Two blocks - one on a table and one hanging - acceleration with friction**

## Homework Statement

h ttp://bildr.no/view/186531

that's a link to an image of the problem

Block A (mass 2.25kg) rests on a table top, it is connected by a horizontal cord passing over a light , frictionless pulley to a hanging block B (mass 1.30kg). The coefficient of kinetic friction between block A and the table is 0.450

After the blocks are released from rest, find the speed of each block after moving 3 cm.

## Homework Equations

## The Attempt at a Solution

I've calculated the normal force for both blocks

Block A = M1g = 2.25*9.81 = 22.07N

Block B = M2g = 1.30*9.82 = 12.7N

I'm a bit unsure on how to calculate the friction force fk for this one, if it had been just a single block sitting on a horizontal then it would've been the friction coefficient * mg

My plan was to use the formula : V^2 = V0^2 + 2a (x-x0)

to find the velocity after 3cm

The blocks will have the same acceleration and the same velocity, but i don't know how to calculate either due to the frictional coefficient.

If the friction wasn't involved, i could've used a=(M2g)/(m1 + m2 )

could someone please point me in the right direction ?