In thrill machine rides at amusement parks, there can be an acceleration of 3g or more. But without head rests, acceleration like this would not be safe. Think why?

A kind of variable that a researcher purposely changes in an investigation is

Which uses motion of water in nature to produce electricity? A. Solar power B. Nuclear power C. Wind power D. Hydroelectric power

Many people are familiar with the fact that a rifle recoils when fired. This recoil is the result of action-reaction force pairs. A gunpowder explosion creates hot gases which expand outward allowing the rifle to push forward on the bullet.

An object is dropped from the top of a 200 m tower. its height above the ground after t seconds is 200 - 4.9t^2. how fast falling after 3 seconds

A 0.10 kg piece of copper at an initial temperature of 95°c is dropped into 0.20 kg of water contained in a 0.28 kg aluminum calorimeter. the water and calorimeter are initially at 15°c.

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.?

A spring gains 2.34 joules of elastic potential energy as it is compressed 0.250 meter from its equilibrium position. What is the spring constant of this spring? (1) 9.36 N/m (3) 37.4 N/m (2) 18.7 N/m (4) 74.9 N/m

Form hypothesis: Where do you think we humans get energy?