Electrons are fired at a rectangular potential energy barrier, once every 221 ms. If the barrier is 2.55 mm thick and has a height that exceeds the energy of the incident electrons by exactly 637 meV, how long on average would you expect to wait for one electron to pass through the barrier

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

A20 cm long spring is attached to a wall. the spring stretches to a length of 22 cm when you pull on it with a force of 100 n. what is the spring constant

Talia is manufacturing rolls of wire for hanging pictures. she needs a material that is so that it can easily be pulled into wire without breaking.