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The motor exerts a force of F=(20t^2) N on the cable, where t is in seconds.?
Determine the speed of the 25 kg crate when t=4s.The coefficients of static and kinetic friction between the crate and the plane are 0.3 and 0.25, respectively.
1 Answer
- JacyLv 71 decade agoFavorite Answer
Apply Newtons' 2nd law:
Σ F = ma
F - ƒ = ma,
where,
friction force: ƒ = (µ_k) mg,
20t² - (µ_k) mg = ma
20t² - 0.25*25*9.81 = 25a
a = 20t² - 61.3 / 25, ......for t = 4, ......=> a = (20*4² - 61.3) / 25 = 10.34 m/s²
v = at = 10.34*4 = 41.39 m/s
