# SPEED OF RELATIVE MOVEMENT

Speed relative to a reference point, usually itself in motion.

## Related Terms

### SHALLOW WATER EFFECT

The effect that due to the depth of water, the speed of the vessel and shape of the vessel's hull causes the vessel to sink deeper in the water especially in shallow water and at high speed. The vessel becomes sluggish in responding to the rudder.

### PLASMA TORCH

A torch in which temperatures as high as 50,000 C are achieved by injecting a plasma gas tangentially into an electric arc formed between electrodes in a chamber; the resulting vortex of hot gases emerges at very high speed through a hole in the negative electrode, to form a jet for welding, spraying of molten metal, and cutting of hard rock or hard metals.

### PILOT BALLOON

A small balloon whose ascent is followed by a theodolite in order to obtain data for the computation of the speed and direction of winds in the upper air.

### PHOTOTUBE CURRENT METER

A device for measuring the speed of water currents in which a perforated disk, which rotates with the current by means of a propeller, is placed in the path of a beam of light that is then reflected from a mirror onto a phototube.

### PERFORMANCE CHART

Graphical representations showing the abilities of rotating equipment at various operating conditions; for example, the performance curve for a compressor would include rotor speed for various intake and outlet pressures versus gas flow rate adjusted for temperature, density, viscosity, head, and other factors.

### PENETRATION SPEED

The speed at which a drill can cut through rock or other material. penetration test

### OVERSPEED GOVERNOR

A governor that stops the prime mover when speed is excessive.

### NONRELATIVISTIC MECHANICS

The study of the dynamics of systems in which all speeds are small compared to the speed of light.

### NEWTON'S LAWS OF MOTION

Three fundamental principles (called Newton's first, second, and third laws) which form the basis of classical, or Newtonian, mechanics, and have proved valid for all mechanical problems not involving speeds comparable with the speed of light and not involving atomic or subatomic particles.

### NEWTON'S FIRST LAW

The law that a particle not subjected to external forces remains at rest or moves with constant speed in a straight line. Also known as first law of motion; Galileo's law of inertia.

### Related questions

MarineProHelp 2018 - 2021