Two model train cars roll to the right. Both have masses of 1Kg. One has a velocity of 2m/s. It catches up with and couples to the other which had a velocity of 1m/s. What is the velocity of the combined mass? m1 v1i + m2 v2i = m1 v1f + m2 v2

Awave with a frequency of 500 hz is traveling at a speed of 100 m/s. what is the wavelength?

Afaulty model rocket moves in the xy-plane (the positive y direction is vertically upward). the rocket's acceleration has components ax(t) = ? t2 and ay(t) = ? ? ? t, where ? = 2.50 m/s4 , ? = 9.00 m/s2 , and ? = 1.40 m/s3 . at t = 0 the rocket is at the origin and has velocity ~v0 = v0x ? i + v0y ? j with v0x = 1.00 m/s and v0y = 7.00 m/s. (a) calculate the velocity and position vectors as functions of time. (b) what is the maximum height reached by the rocket? (c) sketch the path of the rocket. (d) what is the horizontal displacement of the rocket when it returns to y = 0?

In a star, nuclear fusion occurs in the a. photosphere. b. corona. c. radiative zone. d. core.