27. A bicycle wheel on a repair bench can be accelerated either by pulling on the chain that
is on the gear or by pulling on a string wrapped
around the tire. The tire's radius is 0.38 m, while
the radius of the gear is 0.14 m. What force would
you need to pull on the string to produce the
same acceleration you obtained with a force of
15 N on the chain?

3. on your graph, the data points between the black squares are data for elements with atomic numbers 3 through 9. locate these elements on your periodic table. what term or description would you use to identify these elements with respect to the periodic table?

Consider the particle-in-a-box problem in 1d. a particle with mass m is confined to move freely between two hard walls situated at x = 0 and x = l. the potential energy function is given as (a) describe the boundary conditions that must be satisfied by the wavefunctions ψ(x) (such as energy eigenfunctions). (b) solve the schr¨odinger’s equation and by using the boundary conditions of part (a) find all energy eigenfunctions, ψn(x), and the corresponding energies, en. (c) what are the allowed values of the quantum number n above? how did you decide on that? (d) what is the de broglie wavelength for the ground state? (e) sketch a plot of the lowest 3 levels’ wavefunctions (ψn(x) vs x). don’t forget to mark the positions of the walls on the graphs. (f) in a transition between the energy levels above, which transition produces the longest wavelength λ for the emitted photon? what is the corresponding wavele

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?