10. Sally reasoned that if she drove 30 km/hr in one direction over a 180 km distance, and then returned traveling at 60 km/hr over the same distance, that her average speed must be half way between 30 and 60, which is 45 km/hr. Is she right? Why or why not?

The kinetic energy E of an object varies jointly with the object’s mass m and the square of the object’s velocity v . An object with a mass of 50 kilograms traveling at 16 meters per second has a kinetic energy of 6400 joules. What is the kinetic energy of an object with a mass of 70 kilograms traveling at 20 meters per second?

Compute the following problems. Express the answers to the nearer whole number. Use C=3.1416DN12 or DN12 for customary units and C=3.1416DN1000 or DN1000 for metric units. What is the surface speed of a 16-inch diameter surface grinder wheel running at1194 rpm?