Physics of Cricket Bowling

Run Length Mechanics:and also be slowed down in the air. A ball's recoil is
Mass of human * Velocity of stride = Mass of ball *dependant upon the initial velocity and the coefficient
Velocity of release --- (Law of conservation ofof restitution. The release height of the ball is roughly
momentum)--(1)1.8 - 2.2 meters. At 140 km/hr vertical speed with a
For a release velocity of 140 Km/ hr on the ballcoefficient of restitution = 0.5 a ball would recoil up
Mass of ball = = 1.5 Kgto half of its height. But the speed observed (140
Mass of human = 70 KgKm/Hr) will not be released vertically.
Going by equation (1)For a release angle of 45 degrees with the vertical
1.5 * 140 = 70 * V stridethe vertical speed would be 140 * sin 45, the
V stride required of 70 kg human = 3 Km/hrhorizontal speed would be 140 * cos 45. This reduces
V stride required of 60 Kg human = 4 Km/hrto about 100 Km/hr speed at discharge. The recoil
V stride required of 80 Kg human = 2.5 Km/hrheight or the recoil velocity will not get affected by
The run length is a critical factor because of thethe angle of delivery of the ball. It depends only upon
following reasons. The velocity of stride near thethe height of delivery.
crease will depend upon the acceleration provided byMechanics of Short ball and good length ball:
the bowler and the length of his run up.Short ball and length ball depend upon the height
V * V = 2 * a * S ( 2) ( Newton's laws of motion)from which the ball is delivered and the angle from
For a 140 Km/hr release of the ball at a human stridewhich the ball is delivered. It does not matter the
of 3 km/hr or.88 m/sspeed at which the ball is thrown. The mechanics of
(fastest human speed is about 10m/s)the ball will be influenced only because of the Earths
0.88 * 0.88 = 2 * acceleration * 10 ( length of run)gravitational force and no other forces. The location
Acceleration required = 0.032 m/sec * secwhere the ball lands after leaving the bowlers hands
Ball recoil:will depend upon the horizontal component of the
The ball bounce is determined by the coefficient ofvelocity of release.
restitution. A ball will be slowed down after pitching