A ball falls from a shelf. Assuming there is no friction, why is the conservation of mechanical energy independent of mass

Aplane flies directly between two cities, a and b, which are separated by . from a to b, the plane flies into a headwind. on the return trip from b to a, the wind velocity is unchanged. the trip from b to a takes less than the trip from a to b. what is the airspeed of the plane, assuming it is the same in both directions

Find the mass by adding the numbers from the three sliders

Use 4 to 5 complete sentences, explain the concepts of beats and how beats are produces.