Newtons Laws By Kevin Lui and Dennis Tao

Newton’s Laws By Kevin Lui and Dennis Tao

Newton’s First Law of inertia- in the absence of an unbalance applied force, the body at rest remains at rest and a body already in motion remains in motion with a constant velocity. This rule only applies if the object is moving in a straight line. Example of Newton’s First Law

Example Problem If the sum of all the forces acting on a moving object is zero, the object will: ¡ 1. slow and stop ¡ 2. change the direction of its motion ¡ 3. accelerate uniformly ¡ 4. continue moving with constant velocity

Answer Choice (4) because according to Newton's first law, in there is no outside force an object at rest will remain in rest and an object in motion will remain in motion.

Newton’s Second Law The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the object’s mass. Net Force = Mass x Acceleration Example of Newton’s Second Law

Example Problem What is the gravitational acceleration on a planet where a 2 kilogram mass has a weight of 16 N on the planet's surface? ¡ 1. 1/8 m/s^2 ¡ 2. 8 m/s^2 ¡ 3. 10 m/s^2 ¡ 4. 32 m/s^2

Answer Choice (2), because according to Newton's 2 nd law, acceleration is equal to Force divided by mass. Acceleration = Net Force/Mass Acceleration = 16 N/2 kg Acceleration = 8 m/s^2

Newton’s Third Law For every action there is an equal and opposite reaction. Example of Newton’s Third Law

Example Problem A man is pushing a baby stroller. Compared to the magnitude, or amount, of force exerted on the stroller by the man, the magnitude of the force exerted on by the stroller is ¡ 1. zero ¡ 2. smaller but greater than 0 ¡ 3. larger ¡ 4. the same

Answer Choice (4) because according to Newton's 3 rd law, any action has an equal and opposite reaction. So, the magnitude of force the stroller exerts back and the magnitude of force exerted by the man are the same

Homework Holiday Packet Q 7, 36 AMSCO pg 28 Q 98

Demo ¡ ¡ ¡ First Law: http: //www. youtube. com/watch? v=u. OSBC 0 SXVR 4 Second Law: http: //www. youtube. com/watch? v=Uh. CG 0 qo. Y 9 Dc&playnext=1&li st=PLE 7 CB 081021 BD 828 F&index=5 Third Law: http: //www. youtube. com/watch? v=m. NM 5 t. Hou 4 IQ