When an object falls with air resistance, both its acceleration and speed change during its motion. When an object falls in a vacuum, there is no air resistance because there is no air in a vacuum.

1. A rock and a feather are released from rest from the same height with air resistance on.
   Do they hit at the same time? Yes/No (answer shown in blue).
   
   
2. A rock and a feather are released from rest from the same height with air resistance off.
   Do they hit at the same time? Yes/No (answer shown in blue).
   
   
3. A rock and a feather are released from rest from the same height with air resistance on. Determine the time and the speed that each object hits the ground.
   Result:

   Object	Time to impact	Speed at impact
   Rock	2.5 seconds	7 m/sec
   Feather	25 seconds	0.6 m/sec

   
   
4. Repeat the previous exercise with air resistance off.
   Result:

   Object	Time to impact	Speed at impact
   Rock	1.6 seconds	15.7 m/sec
   Feather	1.6 seconds	15.7 m/sec

   
   
5. A rock falls fastest when there is no air resistance
   True/False (answer shown in blue).
   
   
6. A feather falls fastest when there is no air resistance
   True/False (answer shown in blue).
   
   
7. Without air resistance, a rock and a feather fall at the same speed
   True/False (answer shown in blue).
   
   
8. With air resistance, a rock and a feather fall at the same speed
   True/False (answer shown in blue).