Problem 3/107 Page 166, Engineering Mechanics - Dynamics, Meriam and Kraige, 4th Edition
Given: Collar of mass m sliding on a circular frictionless track of radius R and acted on be a constant force F. The collar is at rest at the top of the track.
Find: The speed of the collar when it reaches its rightmost position.
Parameter Values:
m = 0.5 kg
F = 5 N ( cos 30 i + sin 30 j ) = 5 31/2
/2 N i + 2.5 N j
R = 0.2 m
1. Mechanical System: Collar at it travels from top to rightmost position.
2. Free Body Diagram: Not included. Would show weight acting vertically downward, the constant applied force F, and a normal force from the track.
3. Equations:
Work = -m g Dh (gravity) + F . Dr
(constant force) + 0 (force normal to motion)
= -m g (-R)
+ Fx R - Fy R
= ( 0.5 9.81
0.2 + 2.5 31/2 0.2 - 2.5 0.2 ) N m = 1.347 N m
D Kinetic Energy = 1/2 m ( vB2 - 0 ) = 0.25 kg vB2
4. Solve:
1.347 N m = 0.25 kg vB2
vB = (1.347/0.25)1/2 m/s = 2.32 m/s