A box of books weighing 347 N is shoved across the floor by a force of 492 N exerted downward at an angle of 31◦below the hori-zontal.?
The acceleration of gravity is 9.81 m/s2.If μk between the box and the floor is 0.59,how long does it take to move the box 4.70 m,starting from rest?
- NCSLv 76 months agoFavorite Answer
find the net horizontal force
find the net horizontal acceleration
find the time
Fn = mg + FsinΘ = 347N + 492N*sin31º = 600 N
f = µk*Fn = 0.59 * 600N = 354 N
net horizontal force
Fnet = FcosΘ - f = 492N*cos31º - 354N = 67.5 N
a = Fnet / m = 67.5N / (347/9.81 kg) = 1.91 m/s²
from s = ½at²
t = √(2s / a) = √(2 * 4.70m / 1.91m/s²) = 2.22 s
Hope this helps!