GMC SIERRA 1997 Manual page 52

Never hold a baby in your arms while riding in a
vehicle. A baby doesn't weigh much
--
until a
crash. During a crash a baby will become so
heavy you can't hold it. For example,
in
a crash
CAUTION: (Continued)
at only 25 mph (40 km/h), a 12-1b. (5.5 kg) baby
will suddenly become a 240-lb. (110 kg) force
on your arms. The baby would be almost
impossible to hold.
Secure the baby in an infant restraint.
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