GMC 2007 Yukon XL Owner's Manual page 65

CAUTION:
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People should never hold a baby in their
arms while riding in a vehicle. A baby does
not weigh much — until a crash. During a
crash a baby will become so heavy it is not
possible to hold it. For example, in a crash
at only 25 mph (40 km/h), a 12 lb (5.5 kg)
baby will suddenly become a 240 lb
(110 kg) force on a person's arms. A baby
should be secured in an appropriate
restraint.
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