Free Fall
• Free fall is a state of falling free from air
resistance and other forces except gravity.
For Free Fall...
(a) you drop an object from rest at t=0.
(b) velocity acquired = acceleration  time
v=gt
(c)
Distance traveled = 1 Accelerationtimetime
2





2
1
d gt
2





Example Multiple-Choice Questions
1. The two measurements necessary
for calculating average speed are
(a) acceleration and time.
(b) velocity and time.
(c) distance and time.
(d) distance and acceleration.
2. What is the average speed of a horse
that gallops a distance of 10 kilometers
in a time of 30 minutes?
(a) 10km/h
(b) 20km/h
(c) 30km/h
(d) more than 30km/h
3. What is the acceleration of a car that
maintains a constant velocity of
100km/h for 10 seconds?
(a) 0 km/h s
(b) 10 km/h s
(c) 10 m/s2
(d) 1000 km/h s
3. What is the acceleration of a car that
accelerates from rest to 100km/h in 10
seconds?
(a) 0 km/h s
(b) 10 km/h s
(c) 10 m/s2
(d) 1000 km/h s
6. Dan drops a stone down a well and
sees it hit the water 4 seconds later.
Neglecting air resistance, how deep is
this well?
(a) 9.8 m
(b) 19.6 m
(c) 78.4 m
(d) 156.8 m
(e) 39.2 m
7. Dan drops a stone down a well and
sees it hit the water 4 seconds later.
Neglecting air resistance, what is the
speed of impact of the stone?
(a) 9.8 m/s
(b) 19.6 m/s
(c) 4.9 m/s
(d) 78.4 m/s
(e) 39.2 m/s
distance
Speed 
time
Velocity = {speed with a direction}
change
of
velocity
Acceleration =
time interval
g = 9.8
2
m/s
downward
Free Fall
v=gt
2
1
d gt
2