The 20-kg crate is subjected to a force having a constant direction and a magnit
ID: 1548730 • Letter: T
Question
The 20-kg crate is subjected to a force having a constant direction and a magnitude F = 100 N. When s = 15 m, the crate is moving to the right with a speed of 8 m/s. Determine its speed when s = 25 m. The coefficient h of kinetic friction between the crate and the ground is mu _k = 0.25. Based on this above 14.1 quiestion, please solve the problem writen bellow. (i) solve the speed when s = 25m (ii) If the velocity is changed to 4 m/s, analyse the force required to achieved the same speed calculated in (i)Explanation / Answer
1)
Normal reaction on block
N = mg-Fsin30 = mg -0.5F
so net force o block
Fcos30 - u N = ma
ma = Fcos30 - 0.25 mg +0.5x0.25F
ma = Fcos30 + 0.5x0.25F -0.25mg
a = 2.505 m/s^2
velocity at s = 25 m
V^2 u^2 = 2a(25-15)
u = 8
substituting we get
V = 10.68 m/s
b)
we have final and initail velocities
so
we can get a
V^2 - 4^2 = 2a x 10
a = 4.9 m/sec^2
from above equation we have
ma = Fcos30 + 0.5x0.25F -0.25mg
substituting a we get
F = 148.434 N
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.