Manual Chapter 16 __full__: Vector Mechanics For Engineers Dynamics 12th Edition Solutions
vB=vA+ω×rB/Av sub cap B equals v sub cap A plus omega cross r sub cap B / cap A end-sub
While ICR works perfectly for velocities, , because the acceleration of the ICR is rarely zero. You must revert to the relative acceleration vector equations, breaking them down into components to solve for unknown variables. Breakdown of Typical Chapter 16 Problems 1. Planetary Gear Trains
) do not match the manual, trace back to your vector cross-product signs. Conclusion vB=vA+ω×rB/Av sub cap B equals v sub cap
Every point has the same acceleration ( a⃗Gmodified a with right arrow above sub cap G Key Constraint: Since there is no rotation, Fixed-Axis Rotation The body rotates around a stationary point Acceleration components: a⃗Gmodified a with right arrow above sub cap G has tangential ( ) and normal ( ) components. Moment Equation: Often easier to use (Parallel Axis Theorem). General Plane Motion
: When a rigid body moves such that all particles move in parallel paths. Planetary Gear Trains ) do not match the
). This contact point acts as the Instantaneous Center (IC). The center of the wheel (G) moves with velocity The acceleration of the center is
a⃗B=a⃗A+a⃗B/A=a⃗A+(α⃗×r⃗B/A)−ω2r⃗B/Amodified a with right arrow above sub cap B equals modified a with right arrow above sub cap A plus modified a with right arrow above sub cap B / cap A end-sub equals modified a with right arrow above sub cap A plus open paren modified alpha with right arrow above cross modified r with right arrow above sub cap B / cap A end-sub close paren minus omega squared modified r with right arrow above sub cap B / cap A end-sub Separate the vector equations into scalar components. Solve for the unknown angular accelerations ( ) and linear accelerations. Sample Problem Breakdown: Rolling Without Slipping A classic problem in Chapter 16 features a disk of radius General Plane Motion : When a rigid body
Using the principles of three-dimensional motion of rigid bodies, we can solve this problem.
$$a_n = \fracv^2\rho = \frac(80 \text km/h)^2(15 \text m) = 2.37 \text m/s^2$$
Next, the velocity vector was found by taking the derivative of the position vector with respect to time: $$\mathbfv = \fracd\mathbfrdt = 0.2\mathbfi - 0.4\mathbfj$$.
α=dωdt=d2θdt2alpha equals the fraction with numerator d omega and denominator d t end-fraction equals d squared theta over d t squared end-fraction αdθ=ωdωalpha space d theta equals omega space d omega Relative Velocity in General Plane Motion When analyzing two points ( ) on the same rigid body: