Friction patch?

Question

Friction Patch:A 10 kg crate is sliding at a constant speed of 11 m/s along a frictionless horizontal table, when it encounters a friction patch (mus =1.1, muk =0.5). Once the crate enters the friction patch,

a.) What are the sizes of the net force and acceleration of the crate?

size of net force: N

size of acceleration: m/s2

b.) How fast will the crate be going, when it has travelled 4 m across the friction patch?

m/s

Answer 1

F = mus*m*g - muk*m*g or F = (mus - muk)*mg.

Then applying F = ma => a = F/m, because one still has to accelerate the entire mass m.

a.)

size of net force: N = 58.8N

size of acceleration: m/s2 = 5.88m/s^2

b.) 1.47m/s

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