(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A block A (mass m) is projected up a slope at 17 m/s. The coefficient of dynamic friction is 0.27 and θ = 15˚. How long will it take for the mass's speed to drop to 5 m/s?

**Let x direction be along the incline, y direction is normal to incline

2. Relevant equations

[tex]L_1+IMP_{1-2}=L_2[/tex]

1 being point of initial velocity

2 being point of final velocity

3. The attempt at a solution

[tex]L_1+IMP_{1-2}=L_2[/tex]

[tex]mv_i-\mu_dNt=mv_f[/tex] (1)

sum forces in y direction:[tex]N-mgcos(\theta)[/tex] (2)

Sub 2 into 1: [tex]mv_i-\mu_dmgcos(\theta)t=mv_f[/tex]

m (MASS) cancels out and we are left with: [tex]t=\frac{v_f-v_i}{\mu_dmgcos(\theta)}[/tex]

Giving me a value of 3.55 s, whereas the answer should be 1.66 s.

Any help would be appreciated!!

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# Homework Help: Linear Impulse/Momentum

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