If a rock weighing 2,200 n is dropped from a height of 15 m, what is its ke just before it hits the ground? remember, weight is measured in newtons (n), and is equal to mass times gravity. a. 0 j b. 2,224 j c. 147 j d. 33,000 j

Ann walks 80 meters on a straight line 33 ∘ north of east starting at point 1. draw ann's path. represent ann's walk with a vector of length 80 meters. draw the vector starting at point 1. the length given in the display is in meters.

Aparticle of mass m is projected with an initial velocity v0 in a direction making an angle α with the horizontal level ground as shown in the figure. the motion of the particle occurs under a uniform gravitational field g pointing downward. (a) write down the lagrangian of the system by using the cartesian coordinates (x, y). (b) is there any cyclic coordinate(s). if so, interpret it (them) physically. (c) find the euler-lagrange equations. find at least one constant of motion. (d) solve the differential equation in part (c) and obtain x and y coordinates of the projectile as a function of time. (e) construct the hamiltonian of the system, h, and write down the hamilton’s equations (canonical equations) of motion.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.