Physics 11
Force Diagrams
Mr. Jean
The plan:
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Video clip of the day
Force Diagrams
Friction
Friction Practice Questions
Net Forces:
• The existence of an unbalanced force for a
given situation can be quickly realized by
looking at the free-body diagram for that
situation.
Brightstorm Videos:
• Net Forces:
http://www.brightstorm.com/science/physic
s/newtons-laws-of-motion/net-forceresultant-force/
• http://www.youtube.com/watch?v=AFnoBr
hOR4U
Consider the following forces:
Consider the following:
Solutions:
Determine the Net Forces:
Solutions:
Determine the acceleration if the
object had a mass of 2kg:
Solutions:
Practice Questions:
• P. 144
– Question #5 & #6
• Upcoming items:
– Rocket Design Day #1 Thursday
• Research & Introduction
– Quest Assignment #4 due next Sunday
Rocket Design Information:
The Engines:
Rocket Build Goals:
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Nose Cone test
Wing test
Parachute Test
Engine Size Test
Nose Cone Test:
• A proper nose cone must fit inside the
rocket fuselage.
– The fit should be snug
– Nose cone should detach from body when an
individual quickly blows air through the body.
• Do not have your parachute in when testing this!
Wing Test:
• In order to test the strength of the wings. A
individual should be able to hold the entire
rocket by one wing.
– If the wing becomes unglued, falls off or
structurally fails this rocket is not suitable for
flight.
Parachute Test:
• Take a 100g weight and attach parachute
to it. Drop from ceiling with parachute fully
open. The parachute should guide the
weight softly to the ground without
horizontal displacement.
– Common Failures
• Parachute lines break
• Parachute causes horizontal motion
• Issues with parachute design
Engine Test Part #1:
• Engine should have a snug fit to the inside
of the fuselage.
– There MUST be a point where the engine can
not go past.
• However there must remain hollow space to allow
the parachute deployment charge to function
correctly.
– Engines are NOT to be glued into the rocket.
Engine Test Part #2
• Engines should be secured to make sure
that when deployment charge explodes it
does not fire the engine out the back of the
model.
– Rockets MUST HAVE some type of engine
harness preventing the engine from falling out
the bottom end.