- #1

swede5670

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## Homework Statement

The 60 kg block starting at rest is pushed 7.8 m up a ramp at an angle θ = 26.5° to the horizontal in 15 s. If the coeficient of kinetic friction is 0.17:

What is the acceleration of block?

What is the force used to push the block up the ramp?

## Homework Equations

Fnet = ma

Delta X = Vit + (1/2)at^2

Fg=ma

Fkinetic = μ * N

## The Attempt at a Solution

I think I understand the first part,

7.8 = 0*15 + (1/2)(a)(15^2)

7.8 = 112.5a

.069=a

But the second part is what's giving me trouble

Do I need to make an Fnet = ma equation?

If I do I know that it would look like this

Force of Push - Force of friction = ma

Force of Push - Force of friction = (60)(.069)

Can I substitute in this equation? Fkinetic = μ * N for Fk?

Force of Push - (μ * N) = 60* .069

Fpush - (.17 * N) = 4.14

But what is my N force? I think that it would just be mass times acceleration of gravity and in that case:

Fpush - (.17 * (60 * 9.81)) = 4.14

Fpush - 100.06200 = 4.14

Fpush = 104.20200N

I'm not sure if this is right, I appreciate your help in advance.