Isaac Newton's First Law of Motion describes the behavior of a massive body at rest or in uniform linear motion, i.e., not accelerating or rotating. The First Law states, "A body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force." This simply means that things cannot start, stop or change direction all by themselves. It requires some force acting on them from the outside to cause such a change. While this concept seems simple and obvious to us today, in Newton's time it was truly revolutionary. There are many excellent examples of Newton's first law involving aerodynamics. The motion of an airplane when the pilot changes the throttle setting of the engine is described by the first law. The motion of a ball falling down through the atmosphere, or a model rocket being launched up into the atmosphere are both examples of Newton's first law. The motion of a kite when the wind changes can also be described by the first law. 1. A football and a stone has same mass, I. Both have same inertia II. Both have same momentum III. Both have different inertia IV. Both have different momentum 2. The inertia of a moving object depends on: i. Mass of the object, ii. Momentum of the object iii. Speed of the object iv. Shape of the object 3. When a balloon held between the hands is pressed, its shape changes. This happens because, (a) Balanced forces act on the balloon (b) Unbalanced forces act on the balloon (c) Frictional forces act on the balloon (d) Gravitational force acts on the balloon 4. There are two statements, Statement A Newton’s first law in valid from the pilot in an aircraft which is taking off, Statement B Newton’s first law in valid from the observer in a train moving with constant velocity, Which of the following is correct, (a) A only (b) B only (c) Both A and B are correct (d) Both A and B are wrong 5. A water tanker filled up to 2/3 of its height is moving with a uniform speed. On a sudden application of brakes, the water in the tank would, (a) move backward (b) move forward (c) be unaffected (d) rise upwards -------------------------------------------------------------------------------------------------------------------------- More questions to be added shortly...