{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

18 - 2D rigid body rotational kinetics - Work, power, and energy equation

# 18 - 2D rigid body rotational kinetics - Work, power, and energy equation

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

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

View Full Document
2D Rigid Body Rotational Kinetics – Work, Power, and Energy equation Work and power for rotational motion , for constant torqu e W P τ θ τ ω = ⋅Δ = is the angle of rotation or angular displacement ( )/ ave W d P t τ θ τ θ θ = = ⋅Δ Δ Δ e Example A disk with mass 15 Kg and radius 0.4 m is pivoted at its center. A constant torque of 30 Nm supplied by a motor turns the disk from rest. (a) Calculate the work produced by the motor from t = 0 to t = 8 s. (b) Find the average power provided by the motor from t = 0 to t = 8 s. (c) Find the instantaneous power output of the motor at t = 8 s. Ans : (a) 24 kJ (b) 3 kW (c) 6 kW – Energy equation including the rotational motion 1 1 1 1 2 2 2 2 g e g K U U W K U U + + + = + + Rotational kinetic energy K = (1/2) I ω 2 Translational kinetic energy K = (1/2) m υ 2 Gravitational potential energy U g = mgy cm Elastic potential energy U e = (1/2) kx 2 1 2 k W N s μ τ θ = − + Example 1. The slender rod of mass m and length L is pivoted at point O , and it is released from rest as shown at an angle
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}