Aparticle moves along a straight line ox. at a time t(in seconds) the distance x(in metres) from the particle o is given by x=40+12t-t3. how long would the particle travel before coming to rest

Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?

Occurs when an energy source transfers heat directly to another subject space; an example would be an object becoming warm by sitting in the sunshine

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.