Review Unit Three – Rocket Flight - Mini-Lessons L to N Five multiple choice questions Example: Inertia, the principle that an object will stay at rest (if resting), or will keep moving (if already moving) is known as: Newton’s 1st Law of Motion Newton’s 2nd Law of Motion Newton’s 3rd Law of Motion Newton’s 4th Law of Motion One SHORT ANSWER Example: Use Newton’s Laws of Motion to explain why a rocket does not need continual thrust to maintain orbital flight. (Use diagrams to illustrate your answer.) Review Unit Three – Rockets (RKT) A complete answer will include: Newton’s 1st Law states that a body in motion (like a rocket in space) will continue in motion unless acted upon by another force. A rocket’s orbital motion is due to the balance between thrust and gravity.

Mini-Lesson L: Newton’s Three Laws of Motion Sir Isaac Newton (1643-1727) an English mathematician, astronomer, and physicist who is widely recognized as one of the most influential scientists of all time and a key figure in the scientific revolution. First Law: A body at REST will stay at rest, and a body IN MOTION will stay in motion, unless acted on by an outside force (inertia). Second Law: ACCELERTATION happens when a MASS is moved by a FORCE (F = M x A) Third Law: Every force (in one direction) has an equal force in the opposite direction. Cool ROCKET applications - Apollo 13 Launch

Mini-Lesson M: Rocket Engines &Thrust Rocket engines generate THRUST using expanding gases Expanding gases can be generated by: Combustion of a fuel and an oxidizer (O2) – liquid or solid A change in temperature or pressure – steam or pump (our rockets) There are advantages and disadvantages to liquid and solid fuel rocket engines Type of Fuel Advantage Disadvantage Liquid Can be turned on and off Cannot be stored easily (less stable) (LOX, kerosene) Solid Very stable – can be stored and moved easily Cannot be turned off – once lit it burns 100%

Mini-Lesson N: Rockets and Newton’s 3 Laws Rockets & space flight illustrate all three of Newton’s Laws of Motion First Law (inertia) – A rocket in orbit does not need to continually apply thrust. It’s forward motion remains balanced between gravity and forward motion, in the absence of atmospheric drag, “falling” towards the earth at the same rate as the earth is turning. Second Law (F = M x A) – The FORCE a rocket needs to launch is equal to its MASS multiplied by a certain ACCELERATION. The larger the mass, the more acceleration is needed for launch. Third Law – A rocket works by applying a force in ONE direction in order to get a controlled MOTION (thrust) in the opposite direction. No aerodynamic forces are necessary, so rockets work in the vacuum of space.