Answer:
a wheel and axle can also serve as a force multiplier, according to Science Quest from Wiley. If a wheel is attached to an axle, and a force is used to turn the wheel, the rotational force, or torque, on the axle is much greater than the force applied to the rim of the wheel.
Explanation:
Answer:
\d{4}$
Explanation:
In regular expression, the '\d' is used to match digits (from 0 to 9). The '{4}' simply to denote the number of digits needed to match (in this case, 4 in length). Finally, in order to match at the end of the line, the '$' is added.
Therefore the regular expression string for this is
\d{4}$