An
object is falling
under gravity
with terminal velocity.
What is
happening to its
speed?
A It is decreasing to a lower value.
B It is decreasing to zero.
C It is increasing.
D It is staying
constant.
Correct Answer: D (It
is staying constant)
Explanation: When an
object starts falling under gravity its velocity increases due to gravitational
acceleration but it also decreases gradually due to air resistance. At a point
of time the air resistance becomes equal to the gravitational force. At this
stage we say that the object reached its terminal velocity. As the air
resistance and gravitational force both are cancelled by each other, the object
has no acceleration and speed or velocity remains constant for the rest of the
time. This is why droplets of water from rain fall from a very high altitude
but do not strike heavily on the ground.
