um 3) While trick-or-tre ating Jonathan visits a house he\'s heard gives out lar
ID: 1775683 • Letter: U
Question
um 3) While trick-or-tre ating Jonathan visits a house he's heard gives out large Power Ranger candy the time the d dy bars. B ut when he knocks on the door it is his arch rival Hannah that opens it. By oor is open 45 Hannah recognizes Jonathan and begins to close it. Pushing nd with a force of 400 N on the end of the 2.5 m long door. Jonathan at an angle of 80° a really wants the Power Ranger candy bar, and pushes back on the center of the door with a force of 500 N and at an angle of 609 to the door. However Hannah easily wins and laughs as she slams the door in Jonathan's face. How long did it take Hannah to close the door? 1.5m ×2.5 m mass of tme oloar 3okExplanation / Answer
moment of inertia I = (1/2)*m*L^2
torque = r*F*sintheta
torque due to hannah Th = 400*2.5*sin80
torque exerted by jonathan Tj = -500*2.5/2*sin60
net torque = Th + Tj
net torque = (400*2.5*sin80)-(500*2.5/2*sin60)
but net torque = I*alpha
(400*2.5*sin80)-(500*2.5/2*sin60) = (1/2)*30*2.5^2*alpha
alpha = 4.73 rad/s^2
the door has to rotate through an angle of 45 degrees = 45*2pi/360 = 0.785 rad
from equationof motion
theta = wo*t + (1/2)*alpha*t^2
0.785 = 0 + (1/2)*4.73*t^2
t = 0.576 s <<<<----------ANSWER
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.