![]() CATEGORIES: BiologyChemistryConstructionCultureEcologyEconomyElectronicsFinanceGeographyHistoryInformaticsLawMathematicsMechanicsMedicineOtherPedagogyPhilosophyPhysicsPolicyPsychologySociologySportTourism |
Instantaneous Velocity and SpeedYou have now seen two ways to describe how fast something moves: average velocity and average speed, both of which are measured over a time interval The velocity at any instant is obtained from the average velocity by shrinking the time interval
This equation displays two features of the instantaneous velocity Speed is the magnitude of velocity; that is, speed is velocity that has been stripped of any indication of direction, either in words or via an algebraic sign. A velocity of +5 m/s and one of -5 m/s both have an associated speed of 5 m/s. The speedometer in a car measures the speed, not the velocity, because it cannot determine the direction. Example 2-3 The position of a particle moving on an
with Solution. For simplicity, the units have been omitted from Eq. 1-5, but you can insert them if you like by changing the coefficients to 7.8 m, 9.2 m/s, and -2.1 m/s3. The Key Idea here is that velocity is the first derivative (with respect to time) of the position function which becomes
At Exercises 1.5 A hobbyist is testing a new model rocket engine by using it to propel a cart along a model railroad track. He determines that its motion along the 1.6 A car is initially stopped at a traffic light. It then travels along a straight road such that its distance from the light is given by a) Calculate the average velocity of the car for the time interval b)Calculate the instantaneous velocity of the car at i) t =0; ii) t = 5 s; iii) t =10 s Date: 2015-01-12; view: 1098
|