Page 71 - Mechanical Engineer's Data Handbook

60 MECHANICAL ENGINEER'S DATA HANDBOOK

1. I. I I Centre of percussion Sphere
Let:
h=distance from pivot to centre of gravity
p=distance from pivot to centre of percussion
k =radius of gyration of suspended body about The physical meaning of centre of percussion is that it
centre of gravity is the point where an impact produces no reaction at
the pivot point.
hZ + k2
p=-
h 2. I. I2 Vehicles on curved track
Uniform thin rod Horizontal curved track
Skidding speed us = fi

Overturning speed vo=
Cylinder

L
L2 D2
k2 = (- + -); h = ?;
12 16
:11

Curved track banked at angle 8
J( 3
Skidding speed us = gpr 1 +tan -

(1 -p tan 0)
where: p =coefficient of friction,
h = height of CG above ground.

2. I. I3 The gyroscope

The flywheel of moment of inertia I ( =mk2) rotates at
angular velocity o1 about the x axis. An applied
couple C about the z axis produces an angular velocity