A 400 N box is being pushed across a level floor at a constant speed by a force P of 100 N at an angle of 30.0° to the horizontal, as shown in the the diagram below. What is the coefficient of kinetic friction between the box and the floor?
0.19
0.24
0.40
0.22
Explanation
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Fnet = Fx - Fr
at a constant speed, Fnet = 0
:• Fx = Fr
P = 100N
R = mg + Fsin30
--> if the box is pulled, the + becomes -
Fr = uR ===> u(mg + Fsin30)
Fx = Fcos 30
u = Fr/R
u = Fcos30/mg+Fsin30
u = 86.602/450
u = 0.192
weight(W)=400N,acting downward as u can see in d diagram
force(P)=100N,act as to oppose frictional force(Fr)
as my tita value u get it=30° to d floor
normal reaction=N,act upward
Fr and Px act horizontally
W and N act vertically
NB,,,open d angle use sine and closing d angle use cos
Px-Fr=ma
taking Q as my co-efficient of friction,d value to know
Fr=QN,Px=pcos
100cos30°-QN=ma
NB,dey said at constant speed,so acceleration is equa to zero(0)
100cos30°-QN=0
100cos30°=QN______eqn(1) for horizontal component
Py and W acting downward
N acting upward
Py+W=N
Py=Psin
W=400N
100Nsin30°+400N=Q______eqn(2) for vertical component
from eqn(1) and (2)
100cos30=Q×450
Q=0.19
myschool is right
pls to all my dear scholar on this platform, this is the only correct 💯 answer to the question, myschool is wrong and that's because they solve the question using chatgpt, i have too and i arrive at the same answer has the one above but the answer is wrong. one thing I want you all to remember is that chatgpt is just a bot even the developer are collecting your datas on it to improve it response because it's prone to mistakes. mind you never use chatgpt to solve complex questions like dis one instead try using textbooks and other resources that really analyse physics in details. im also going to drop an explanation below so that myschool can make amendments. and if you are still confused, open your all inclusive physics textbook to page 24. a similar question like dis was treated there. feel free to contact me for full detailed explanation
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Resolving into horizontal and vertical components
Vertical= Psin30= 100sin30= 50N
Horizontal= Pcos30= 100cos30= 86.6N
Vertical component= R + Psin30
Remember R is 400N
400+50= 450N
Horizontal component= F=Pcos30
=86.6N
Now to find coefficient of friction
F=uR
86.6=450u
u= 86.6÷450= 0.192=0.19
what if you solve finish come fail the question your time everything gone better skip it and come to it later or pick randomly
