2. Corvette speeds up to 10mph quickly General Motors mistakenly calls this car “fast.” Fast has to do with the speed limit. Even if it’s only going 10 mi/hr, the Corvette does have an impressive acceleration. 2015 Chevy Corvette Z06

3. How quickly does a Corvette get to 10mph? If the acceleration of a Corvette is 9m/(s*s), how quickly in seconds does it get to 10mph? a. 0.5; b. 1.0; c. 1.5; d. 2.0; e. none are close Car and Driver

4. Create a step by step solution: 1.Sketch 2.Convert to standard units: 3.List the variables we know and want: 4.Pick the physics equation: 5.Algebra: 6.Arithmetic: 7.Letter answer: Optional: Estimate the uncertainty. Comment on the numbers. 60sec=1min 1609m=1mi 2.24mi/hr=1m/s 0.0254m=1in 1.v=x/tBasic. (a isn’t involved.) If needed, v ave =(x-xo)/(t-to); v ave =(v+vo)/2 2.a=v/tBasic. (x isn’t involved.) Often: a=(v-vo)/t; 3.x=vo*t+at 2 /2Comes from Eqs. 1&2. Handy if no v 4.v 2 =vo 2 +2axComes from Eqs. 3&4. Handy if no t.

5. Step by step solution: 1.Sketch 2.Convert v units: v=10[mi/hr]*[1m/s]/[2.24mi/hr]=4.5m/s 3.Pick the variables we know and want:vo, v, a, t=? 4.Pick the equation: v=10 t=? 1.v=x/tBasic. (a isn’t involved.) If needed, v ave =(x-xo)/(t-to); v ave =(v+vo)/2 2.a=(v-vo)/tBasic. (x isn’t involved.) ; 3.x=vo*t+at 2 /2Comes from Eqs. 1&2. Handy if no v 4.v 2 =vo 2 +2axComes from Eqs. 3&4. Handy if no t. Slope= a=9.08m/s*s

6. Step by step answer continued 5. Algebra:t=(v-vo)/a 6.Arithmetic: t=(4.5m/s-0)/9.08(m/s 2 ) =0.50s 7.Answer: a. Comment: The GM ad person is confused about the difference between speed and acceleration. In this test the car doesn’t show high speed, but the quick increase in speed shows a big value of acceleration and that reflects the powerful engine compared to the car’s mass: F=ma