There is a 30 g sample of be-11. it has a half-life of about 14 seconds.
how much will be left after 28 seconds?
a. 3.75 g
b. 7.5 g
c. 15 g
d. 30 g

How have the competing explanations' experiments on atoms affected the development of the atomic model?

Assume this car is driven off a cliff . how many arrows of force need to be drawn in the free body diagram? assume no air resistance -five -one -three -four

Consider a double atwood machine constructed as follows: a mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. the other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. using two suitable generalized coordinates, set up the lagrangian and use the lagrange equations to find the acceleration of the mass 4m when the system is released. explain why the top pulley rotates even though it carries equal weights on each side.