Asheet of gold weighing 12.0 g with an initial temperature of 15 °c is placed flat on a 20.0g plate of iron that has been heated to 55°c. what is the final temperature of both pieces of metal? the specific heat of iron is 0.449 j/g°c and the specific heat of gold is 0.129 j/g°c.

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.

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection

Two polarizers are oriented at 40∘ to each other and plane-polarized light is incident on them. if only 16 percent of the light gets through both of them, what was the initial polarization direction of the incident light?