A child with a mass of 55 kg is on a swing. If the length of the chains of the swing are 4.6 m, the child would complete a full swing every what seconds?

How will the system respond to a temperature increase?

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.