Matter & MotionOutlineQuestionsAnswersMatter & MotionOutline1. Isaac Newton2. Motion - Terms & Definitions * Speed * Velocity * Acceleration > Change in speed and/or direction3. Laws of Motion * 1st Law: Constant velocity in absence of net force. * 2nd Law: a = F/m > Example: falling through the atmosphere * 3rd Law: action = reaction > Example: catching a ball > Example: rocket propulsion * Video: Newton in SpaceQuestions1. Ques. #1, pg. 95.2. Ques. #2, pg. 95.3. A force applied to a mass results in a certain acceleration. Applying twice the force will resultin what acceleration? Applying one-third the force will result in what acceleration?4. If the same force is applied to an object (A) with mass of 1 kilogram and to another object (B)with mass 3 kilogram which object will experience the greater acceleration? By how many timesmore?5. A body is observed to move along a perfectly straight line at constant speed. Is there a force acting on the body? Explain.6. A body is observed to move along a circular path at constant speed. Is there a force acting on the body? Explain.7. Explain the principle of "action and reaction" that allows rockets to be propelled through the vacuum of space.Answers1. Speed specifies only the rate of motion; e.g., 50 mi/hr or 100 km/s. Velocity specifies both rate of motion and direction of motion; e.g., 50 mi/hr, north; 100 km/s, up. Rounding a curve in your car while keeping the speed constant would result in changing velocity as the direction of motion of the car changes as it rounds the curve. We would say that the car is accelerating, even though its speed remains constant.2. Acceleration expresses the rate of change of velocity. m/s/s should be read "meters per second per second:" this expresses the rate at which speed (in this case) changes. For example, suppose the acceleration of an object is 3 m/s/s. This means that that object gains 3 m/s of speed for every second it maintains the acceleration. So, if it starts from rest: after 1 sec, its speed is 3 m/s; after 2 sec, 6 m/s; after 3 sec, 9 m/s, and so on: speed = acceleration * time.3. a = F/m. So, twice the force results in twice the acceleration. Applying one-third the force will result in one-third the acceleration.4.. The 1 kg object will experience 3 times the acceleration of the 3 kg object. According to Newton's 2nd law (a = F/m), there is an inverse relationship between a and m.5. Well, there could be forces acting on the body, but they must all combine to yield zero net force as motion at constant speed along a straight line (i.e., zero acceleration) requires zero net force, according to Newton's 2nd law.6. There must be a net force acting. Despite the constant speed, the motion described is accelerated motion as the direction of motion is changing. If an acceleration exists, there must be a nonzero net force acting on the body.7. The rocket expels material (combustion products); this material responds by pushing the rocket
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