A braking system loses 25% of its energy consumed in useful energy. What is its energy efficiency?

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

Ineed the answers for these promblems i have

Aboat radioed a distress call to a coast guard station. at the time of the call, a vector a from the station to the boat had a magnitude of 45.0 km and was directed 15.0° east of north. a vector from the station to the point where the boat was later found is = 30.0 km, 15.0° north of east. what are the components of the vector from the point where the distress call was made to point where the boat was found? in other words, what are the components of vector c = b - a?