A train is moving with a velocity of 70 km/h. If north is taken as the positive direction, what is the direction of movement of the train?

A. It is moving north.
B. It is moving south.
C. It is moving south but is speeding up.
D. It is moving north but is speeding up.

Ajet plane has a sound level of 120 db at a distance of 60 m. what is the q23. sound level at a distance of 6.0 km? (60)2 (6000)? om solution 80db db, hint: 16x assume ultrasound waves travel through the body of an animal at 1540 q24. m/s. if a 30,000 hz signal were reflected off a portion of a heart which was moving toward the source at 3 m/s, what frequency signal would return to the stationary source? solution 30.117hz

The solid that is formed and usually sinks to the bottom of a solution is the

The protons in a nucleus are approximately 2 ✕ 10^−15 m apart. consider the case where the protons are a distance d = 1.93 ✕ 10^−15 m apart. calculate the magnitude of the electric force (in n) between two protons at this distance.