IN: Under federal law, airsoft guns are not classified as firearms and are legal for all ages. People under the age of 18 are not permitted to buy airsoft guns over the counter in stores. However, a person of any age may use one (with the permission of their parents, of course, for anyone under 18). This is also the case for the laws in each state. However, in some major cities, the definition of a firearm within their respected ordinances includes propulsion by spring or compressed air, thus making airsoft subject to applicable laws. For example, airsoft guns within the state of California can only be bought by a person above the age of 18. However, no laws indicate an age requirement to sell airsoft guns. Generally speaking, toy, look-alike, and imitation firearms must have an orange tip during shipping and transportation.
is there an age limit for bb guns?

OUT: no

IN: In a closed system, no mass may be transferred in or out of the system boundaries. The system always contains the same amount of matter, but heat and work can be exchanged across the boundary of the system. Whether a system can exchange heat, work, or both is dependent on the property of its boundary.
can work be done in a closed system?

OUT: yes

IN: The major railway bridge described in the novel and film didn't actually cross the river known at the time as the Kwai. However, in 1943 a railway bridge was built by Allied POWs over the Mae Klong river -- renamed as a result of the film Khwae Yai in the 1960s -- at Tha Ma Kham, five kilometres from Kanchanaburi, Thailand. Boulle had never been to the bridge. He knew that the railway ran parallel to the Kwae for many miles, and he therefore assumed that it was the Kwae which it crossed just north of Kanchanaburi. This was an incorrect assumption. The destruction of the bridge as depicted in the film is also entirely fictional. In fact, two bridges were built: a temporary wooden bridge and a permanent steel/concrete bridge a few months later. Both bridges were used for two years, until they were destroyed by Allied bombing. The steel bridge was repaired and is still in use today.
is the bridge on the river kwai still there?

OUT: yes

IN: The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) and colloquially Great Britain (GB) or simply Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, the United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands. Northern Ireland is the only part of the United Kingdom that shares a land border with another sovereign state--the Republic of Ireland. Apart from this land border, the United Kingdom is surrounded by the Atlantic Ocean, with the North Sea to its east, the English Channel to its south and the Celtic Sea to its south-south-west, giving it the 12th-longest coastline in the world. The Irish Sea lies between Great Britain and Ireland. With an area of 242,500 square kilometres (93,600 sq mi), the United Kingdom is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants. Together, this makes it the fourth-most densely populated country in the European Union (EU).
is the united kingdom a part of europe?

OUT:
yes