How do you find speed from temperature and mach?

The velocity of car is 80.0 miles per hour. what is the velocity of car in meters per second? (1 km -0.621 miles) m/s

You are traveling in a car going at a constant speed of 100km/h down a long, straight highway. you pass another car going in the same direction which is traveling at a constant speed of 80km/h. as measured from your car's reference frame this other car is traveling at −20km/h. what is the acceleration of your car as measured from the other car's reference frame? what is the acceleration of the other car as measured from your car's reference frame?

In which of the following is positive work done by a person on a suitcase