Velocity, wavelength, and frequency.
Wave velocity (v) is how fast a wave propagates in a given medium. Its unit is meter per second. Check the speed calculator for more information about speed and velocity.
Wavelength (λ) is the distance over which the shape of a wave repeats. It depends on the medium in which a wave travels. It is measured in meters.
Frequency (f) of a wave refers to how many times (per a given time duration) the particles of a medium vibrate when the wave passes through it. The unit of frequency is Hertz or 1/second.
Explanation:
Newton's law of universal gravitation states that every object attracts every other object with a force. For any two objects, this force is directly proportional to the mass of each object. The greater the masses, the greater the force of attraction between them. Newton also deduced that this force decreases as the square of the distance between the centers of the objects increases. The farther away the objects are from each other, the less the force of attraction between them.
Answer:
1.38*10^18 kg
Explanation:
According to the Newton's law of universal gravitation:

where:
G= Gravitational constant (6.674×10−11 N · (m/kg)2)
ma= mass of the astronaut
mp= mass of the planet

so:
