Magnitude of a person in a rocket sled as braked and certainly would have been lethal to him. The ability of a woodpecker to withstand
such huge acceleration magnitudes is not well understood, but there are two main arguments.
(1) The woodpecker's motion is almost along a straight line. Some researchers believe that
concussion can occur in humans and animals when the head is rapidly rotated around the neck
(and brain stem), but that it is less likely in straight-line motion. (2) The woodpecker's brain is
attached so well to the skull that there is little residual movement or oscillation of the brain just
after the impact and no chance for the tissue connecting the skull and brain to tear.
PRACTICE PROBLEMS
6. An electric vehicle starts from rest and accelerates at a rate of 2.0 m/s in a straight line until it reaches as
then slows at a constant rate of 1.0 m/s² until it stops. (a) How much time elapses from start to stop? (b
travel from start to stop?
7. On a dry road, a car with good tires may be able to brake with a constant deceleration of 4.92 m/s?. (a
initially travelling at 24.6 m/s, take to stop? (b) How far does it travel in this time? (c) Graph x versus tand v versus t for deceleration