Sally is pushing a shopping cart with a force of 20 n. because the wheels are stuck, the friction caused by the ground is exerting a force of 8 n in the opposite direction. calculate the net force on the shopping cart including an arrow indicating what direction the shopping cart is going

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.