Which statement is true for a sound wave entering an area of warmer air?

a. the wave travels faster and with the same wavelength.
b. the wave travels at the same speed but with an increased wavelength.
c. the wave travels at the same speed and with the same wavelength.
d. the wave travels slower and with an increased wavelength.
e. the wave travels faster and with an increased wavelength.

Can someone explain to me how to do this problem ?

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.

*drag each tile to the correct location in the sequence* the table shows chronological events in the life of our sun, a medium-sized star. place the missing events into the correct rows of the table.