# 01-28-20 Notes

```LCPA βͺ PHYSICS (MS.APPEL)
5-1 NOTES: CIRCULAR MOTION
Name:
Page 1 of 2
Date: 10-30-17
Period:
Circular Motion
Notes
Linear vs. Circular Motion
Quantity
Linear Motion
Speed + Direction
Direction of the object’s motion
Circular Motion
Speed stays the same
Direction is tangent to the circle
πΆβππππ ππ π£ππππππ‘π¦
Speed does not change;
Direction changes
Direction—Toward the center of the
circle
Velocity
π‘πππ
Acceleration
Force
Due to a push/pull
Direction of the push/pull
Push or pull
πΉ = π∗π
In the direction of the acceleration
Looking at Circular Motion
Centripetal force – “center seeking”
Centrifugal force – “center fleeing” ο  Fictitious! (Fake!)
Direction is toward the center of
circle
LCPA βͺ PHYSICS (MS.APPEL)
5-1 NOTES: CIRCULAR MOTION
Name:
Page 2 of 2
Date: 10-30-17
Period:
Circular Motion Problems
Important Quantities
ο·
Frequency (f):
πππππ’ππππ¦ =
Example:
5 revolutions in 40 seconds.
π=
ο·
ππ’ππππ ππ πππ£πππ’π‘ππππ
πππ£
→ [
]
π‘πππ
π ππ
Velocity (v): π£ =
πππ π‘ππππ
π‘πππ
→ [
π
π ππ
5 πππ£
πππ£
= 0.125
40 sec
π ππ
]
π£ = 2πππ
ο·
Centripetal Acceleration (ac):
ππ =
ο·
π£2
π
Centripetal Force (Fc):
ππ£ 2
πΉπ = ππ =
→ [π]
π
Example: Captain Chip, the pilot of a 60,500 kg jet plane, is told that he must remain in a holding pattern
over the airport until it is his turn to land. If Captain Chip flies his plane in a circle whose radius is 50 km once
every 30 min, what centripetal force must the air exert against the wings to keep the plane moving in a
circle?
m = 60,500 kg
# rev = 1
Time = 30 minutes = 180 seconds
f =?
v=?
r = 50 km = 50,000 m
Fc= ?
1 πππ£
πππ£
= 0.0006
180 π ππ
π
πππ£
π
π£ = 2π(50,000 π) (0.0006
) = 175
π
π
π=
π 2
(175 π  )
πΉπ = π ∗ π = (60,500 ππ) (
) = 36, 900 π
50,000 π
```