Applications of ultrasonic and infrasonic sound waves

Can you think of a way a rock unit with an older fossil could be above a rock until with a younger fossil? describe the scenario.

Abird sitting high in a tree is an example of what type of wnergy

The motor m applies a time-varying force of f (200 t) n, where t is in seconds. box b with mass 200 kg starts from rest, and the coefficients of kinetic and static friction are 0.2 and us 0.3 the acceleration due to gravity is g 9.8 m/s2 b 300 a) find the time ' when the box starts to move. b) calculate the speed of the crate at 3 s c) calculate the power delivered by the motor at t 3 s