Inch Per Second (in/s)

US & ImperialCurrent unit

Exactly 0.0254 m/s. Used for tape speeds.

1 inch per second = 0.0254 meters per second (exactly).

About the inch per second

Tape recording standardized on inch per second, often written ips. The Compact Cassette, introduced by Philips in August 1963, runs at 1 7/8 ips, which is 4.7625 cm/s, since 1.875 times 2.54 gives that figure. Open-reel machines used a ladder of speeds, each double the one below: 3 3/4 ips (9.525 cm/s), 7 1/2 ips (19.05 cm/s), 15 ips (38.1 cm/s) and 30 ips (76.2 cm/s).

Some dictation machines ran at half the cassette speed, 15/16 ips, or about 2.38 cm/s. The unit rests on the international inch of exactly 25.4 mm, so one inch per second is exactly 0.0254 m/s, and NIST lists the conversion as exact. A cassette moves at about 0.0476 m/s, which is 0.171 km/h.

Sources: Wikipedia: Compact Cassette; NIST SP 811 Appendix B.8: conversion factors; Wikipedia: Orders of magnitude (speed)

Inch Per Second conversion chart

1 inch per second expressed in every other speed unit:

More US & Imperial units

• mile per hour (speed)
• foot per second (speed)
• foot per minute (speed)
• mile per second (speed)
• inch (length)
• foot (length)
• yard (length)
• mile (length)
• thou (length)
• league (length)
• furlong (length)
• chain (length)
• rod (length)
• link (length)
• hand (length)
• pound (weight & mass)

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