English system

Problem 1003
A stone is thrown vertically upward and return to earth in 10 sec. What was its initial velocity and how high did it go?
 

Problem 1002
On a certain stretch of track, trains run at 60 mph (96.56 kph). How far back of a stopped train should be a warning torpedo be placed to signal an oncoming train? Assume that the brakes are applied at once and retard the train at the uniform rate of 2 ft/sec² (0.61 m/s²).
 

SI Base Units

The International System of Units (SI) define the following base units
 

Meter (m)
The length of the path traveled by light in a vacuum during a time interval of 1/299 792 458 of a second.
 

Kilogram (kg)
Equal to the mass of the international prototype of the kilogram. The prototype is an alloy of 90% platinum and 10% iridium. It was manufactured in the 1880s and kept with its six official copies in a vault at the BIPM.
 

Second (s)
The base unit of time. It is the duration of 9 192 631 770 periods of radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
 

Ampere (A)
A constant electric current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in a vacuum, would produce between these conductors a force equal to 2 × 10^-7 newton per meter of length.
 

Kelvin (K)
The fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
 

Candela (cd)
Unit for luminous intensity. A source that emits monochromatic radiation of frequency 540 × 10¹² hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.
 

Mole (mol)
Unit for quantity of matter. The amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.