A vertical spring has a spring constant of 100. Newtons per meter. When an object is attached to the bottom of the spring, the spring changes from its unstretched length of 0. 50 meter to a length of 0. 65 meter. The magnitude of the weight of the attached object is.

Which of the following always exist between two objects having mass ● elastic force ● contact force ●gravitational force ●magnetic force

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.

Which object has the least amount of kinetic energy? a. a car driving down a road b. a soccer ball rolling down a hill c. a bicycle locked to a bike rack d. a satellite orbiting earth