How much work is required to stop an electron (m= 9.11x10-31kg) which is moving with an initial speed of 3.06x106m/s?

Waves are used in many practical applications to support work, entertainment, and health. one example is the use of ultrasound imaging to safely track the development of a growing fetus. what is a specific example of a practical application of waves in medicine, entertainment, safety, or other fields? provide a brief explanation of how the properties of waves are useful to that application.