Friction is caused by two solids rubbing together quickly.
Answer: A,B, and E
Explanation: Just checked I got them right:)
Answer: C
Explanation:
A collision in which the objects stick together is sometimes called “perfectly inelastic“
Answer:
Explanation:The rate of decrease of velocity is given with respect to displacement. As v approaches zero when s approaches 39, it can be written as
![\frac{dv}{ds} =-19/39\\m=\frac{dv}{ds}\\Hence\\v=ms+c\\](https://tex.z-dn.net/?f=%5Cfrac%7Bdv%7D%7Bds%7D%20%3D-19%2F39%5C%5Cm%3D%5Cfrac%7Bdv%7D%7Bds%7D%5C%5CHence%5C%5Cv%3Dms%2Bc%5C%5C)
where c=19
![v=-\frac{19}{39} *s+19\\](https://tex.z-dn.net/?f=v%3D-%5Cfrac%7B19%7D%7B39%7D%20%2As%2B19%5C%5C)
when s=8 we have
![v=-\frac{19}{39} * 8 +19\\v=15.1 m/s](https://tex.z-dn.net/?f=v%3D-%5Cfrac%7B19%7D%7B39%7D%20%2A%208%20%2B19%5C%5Cv%3D15.1%20m%2Fs)
hence a can be found by the chain rule
![a=\frac{ds}{dt} \frac{dv}{ds}\\a=v*\frac{dv}{ds}\\a=15.1 *-\frac{19}{39}\\a=7.357 m/s^2](https://tex.z-dn.net/?f=a%3D%5Cfrac%7Bds%7D%7Bdt%7D%20%5Cfrac%7Bdv%7D%7Bds%7D%5C%5Ca%3Dv%2A%5Cfrac%7Bdv%7D%7Bds%7D%5C%5Ca%3D15.1%20%2A-%5Cfrac%7B19%7D%7B39%7D%5C%5Ca%3D7.357%20m%2Fs%5E2)
From the equation
![v=-\frac{19}{39} *s+19\\](https://tex.z-dn.net/?f=v%3D-%5Cfrac%7B19%7D%7B39%7D%20%2As%2B19%5C%5C)
the s in term of t can be found
![v=\frac{ds}{dt} \\\int\limits {v} \, dt =\int\limits {} \, ds\\\int\limits {-\frac{19}{39} *s+19} \, dt=\int\limits {} \, ds\\\\\int\limits^t_0 {} \, dt=\int\limits^s_0 {\frac{1}{-\frac{19}{39} *s+19} } \, ds](https://tex.z-dn.net/?f=v%3D%5Cfrac%7Bds%7D%7Bdt%7D%20%5C%5C%5Cint%5Climits%20%7Bv%7D%20%5C%2C%20dt%20%3D%5Cint%5Climits%20%7B%7D%20%5C%2C%20ds%5C%5C%5Cint%5Climits%20%7B-%5Cfrac%7B19%7D%7B39%7D%20%2As%2B19%7D%20%5C%2C%20dt%3D%5Cint%5Climits%20%7B%7D%20%5C%2C%20ds%5C%5C%5C%5C%5Cint%5Climits%5Et_0%20%7B%7D%20%5C%2C%20dt%3D%5Cint%5Climits%5Es_0%20%7B%5Cfrac%7B1%7D%7B-%5Cfrac%7B19%7D%7B39%7D%20%2As%2B19%7D%20%7D%20%5C%2C%20ds)
![t=-\frac{39}{19} ln(\frac{s-39}{39} )\\](https://tex.z-dn.net/?f=t%3D-%5Cfrac%7B39%7D%7B19%7D%20ln%28%5Cfrac%7Bs-39%7D%7B39%7D%20%29%5C%5C)
Hence it can be seen that if s approaches 39 the t function becomes undefined hence s is never 39m
Kinetic energy<span> increases with the square of the velocity (KE=1/2*m*v^2). If the velocity is doubled, the KE quadruples. Therefore, the </span>stopping distance<span> should increase by a factor of four, assuming that the driver is </span>can<span> apply the brakes with sufficient precision to almost lock the brakes.</span>