{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Homework8-F09 - Homework8 Chapt 11 12 Delivering Rescue...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Homework8 Chapt. 11 & 12 Delivering Rescue Supplies You are a member of an alpine rescue team and must project a box of supplies, with mass , up an incline of constant slope angle so that it reaches a stranded skier who is a vertical distance above the bottom of the incline. The incline is slippery, but there is some friction present, with kinetic friction coefficient . Ei(total)-f k Δ S = Ef(total) Ki = 0 , Ui = mgh, f k = μ k N = = μ k mg cos α , Δ S = h/sin α Kf = ½ mV f 2 , Uf = 0 Therefor ½ mV f 2 = mgh - μ k mg cos α ·h/sin α Vf = 2 2 cos / sin k gh gh μ α α + 12.22. Model: The disk is a rotating rigid body. Visualize: The radius of the disk is 10 cm and the disk rotates on an axle through its center. Solve: The net torque on the axle is A A A B B B C C C D D D sin sin sin sin (30 N)(0.10 m)sin( 90 ) (20 N)(0.050 m)sin90 (30 N)(0.050 m)sin135 (20 N)(0.10 m)sin0 3 N m 1 N m 1.0607 N m 0.94 N m F r F r F r F r τ φ φ φ φ = + + + = - ° + ° + ° + ° = - + + = - Assess: A negative torque means a clockwise rotation of the disk. 12.27. Model: Two balls connected by a rigid, massless rod are a rigid body rotating about an axis through the center of mass. Assume that the size of the balls is small compared to 1 m. Visualize:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
We placed the origin of the coordinate system on the 1.0 kg ball.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}