What will cause a backpack sitting on the floor of the school bus to suddenly fly forward

A dolphin emits ultrasound of 100kHz and uses the timings of reflection to determine the position of objects in the water. What is the wavelengths of this ultrasound? Note the speed of sound in water is 1480m/s.

A car traveling at 26 m/s starts to decelerate steadily. It comes to a complete stop in 13 seconds. What is its acceleration?

A statue is to be 'scaled down.' It will have its size changed without changing its shape. It starts with an initial volume of 3.25 m3 and ends up with a final volume of 1.00 m3.

Explain what happens when a massive star ends its life as a supernova.

A solenoid is built with 870 turns uniformly distributed over a length of 0.390 m to produce a magnetic field of magnitude 1.00 * 10-4 T at its center. What is current necessary for this to happen? 17.4 mA 35.7 mA 74.9 mA

The index of refraction of silicate flint glass for red light is 1.620 and for violet light is 1.660. A beam of white light in this glass strikes the glass-air interface at a 25.50∘ angle of incidence and refracts out into the air.

The locations of the major pressure and wind systems on the earth:

Which statements correctly describe the properties of heat? Select all that apply. Heat is an essential component of life on Earth. Heat is energy that flows from one object to another. Heat flows from a hotter object to a colder one.

A book is sitting on a table at rest. Which of the following best describes the forces acting on the book? A.

When NASA's Skylab reentered the Earth's atmosphere on July 11, 1979, it broke into a myriad of pieces. One of the largest fragments was a 1770-kg lead-lined film vault, and it landed with an estimated speed of 120 m/s.?