When the net force acts at right angles to an object’s motion, what does it do to the object’s motion? a. it changes the object’s speed
b. it changes the object’s direction
c. it changes both the speed and direction of the object’s motion.

An important dimensionless parameter concerned with very high-speed flow is the mach number, defined as v/c, where v is the speed of the object such as an airplane or projectile, and c is the speed of sound in the fluid surrounding the object. for a projectile traveling at 1170 mph through air at 50 ˚f and standard atmospheric pressure, what is the value of the mach number?