The ball is dropped from a certain height and is falling to the ground. If its acceleration is a constant 9.8 meters per second squared, how many seconds would it have dropped when the velocity is 49.0 m/s ? A. 4.9 secs
B. 4 secs
C. 5 secs
D. 9.8 secs

The experiment was repeated many years later but the gases were mixed in a different type of container. a white solid was obtained which was xenon fluoride. predict whether you think 1) krypton and 2) radon will react with fluorine. explain reasons for your predictions

Mechanical energy is when the amount of kinetic and potential energies added together remains the same. conserved created lost

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.