Ablue train of mass 50 kg moves at 4 m/s toward a green train of 30 kg initially at rest. the trains collide. after the collision the green train moves with a speed of 3 m/s. what is the final momentum of the blue and green train combined?
a. 90 kgm/s
b. 110 kgm/s
c. 50 kgm/s
d. 200 kgm/s

What is a possible result of higher air temperature caused by global warming

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.