projectilemotion.ppt - EIUux1.eiu.edu/~cblehman/lectures/projectilemotion.pdf · Page 1 Projectile...

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Page 1 Projectile Motion Projectile Motion Projectile Motion Feeding the Monkey Feeding the Monkey (Banana Gun) (Banana Gun) Where does the zookeeper aim if he wants to hit the monkey? ( He knows the monkey will let go as soon as he shoots ! ) Feeding the Monkey... Feeding the Monkey... If there were no gravity, simply aim at the monkey r = r 0 r =v 0 t Feeding the Monkey... Feeding the Monkey... r = v 0 t - 1 / 2 g t 2 With gravity, still aim at the monkey! r = r 0 - 1 / 2 g t 2 Banana hits monkey! Projectile: An Object Moving Projectile: An Object Moving Solely Under Influence of Gravity Solely Under Influence of Gravity Horizontally Launched Projectile Horizontally Launched Projectile

Transcript of projectilemotion.ppt - EIUux1.eiu.edu/~cblehman/lectures/projectilemotion.pdf · Page 1 Projectile...

Page 1: projectilemotion.ppt - EIUux1.eiu.edu/~cblehman/lectures/projectilemotion.pdf · Page 1 Projectile Motion Projectile Motion Feeding the Monkey (Banana Gun) Where does the zookeeper

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Projectile MotionProjectile Motion

Projectile Motion

Feeding the MonkeyFeeding the Monkey(Banana Gun)(Banana Gun)

� Where does the zookeeper aim if he wants to hit the monkey?

( He knows the monkey willlet go as soon as he shoots ! )

Feeding the Monkey...Feeding the Monkey...

� If there were no gravity, simply aim

at the monkey

r = r0

r =v0t

Feeding the Monkey...Feeding the Monkey...

rr = vv0 t -1/2 gg t

2

� With gravity, still aim at the monkey! rr = r0 -

1/2 gg t2

Banana hits

monkey!

Projectile: An Object Moving Projectile: An Object Moving Solely Under Influence of GravitySolely Under Influence of Gravity Horizontally Launched ProjectileHorizontally Launched Projectile

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Projectile MotionProjectile MotionProjectile VelocitiesProjectile Velocities

Net Force in FreefallNet Force in Freefall

Horizontal

Motion

Vertical

Motion

Net Force NO

YES – force of gravity –downward

Acceleration NO

YES – “g” is downward at about 10 m/s/s

Velocity Constant

Changing by about 10 m/s each second

Independence of x & y MotionsIndependence of x & y Motions

t (s) Vy(m/s) Y (m)

0 0 0

1 10 5

2 20 20

3 30 45

4 40 80

t 10 t 5t2

X (m)

0

5

10

15

20

vxt

For Vx= 5 m/s

Projectile Launched at AngleProjectile Launched at Angle Projectile Launched at Angle Projectile Launched at Angle -- 22

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Monkey ZookeeperMonkey Zookeeper Monkey Monkey –– Zookeeper Zookeeper –– No GravityNo Gravity

Monkey Zookeeper Monkey Zookeeper -- FastFast Monkey Monkey –– Zookeeper Zookeeper -- SlowSlow

Projectile TrajectoriesProjectile Trajectories

Complementary

angles have equal

ranges

Satellite MotionSatellite Motion

�If superman threw a rock fast enough … it would orbit the earth (if there were no air resistance

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Satellite = Fast ProjectileSatellite = Fast Projectile

� Since the earth’s surface curves away from the horizontal by 5 m for every 8000 m tangent to the surface

� V = 8000 m/s = 8 km/s

Satellite PeriodsSatellite Periods

� For a satellite close to the Earth, the period (the time for a complete orbit about the Earth) is about 90 minutes.

� For higher altitudes, the orbital speed is less, distance is more, and the period is longer.

� For example, communication satellites located in orbit 5.5 Earth radii above the surface of the Earth have a period of 24 hours.

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