Actinium-226 has a half-life of 29 hours. if 10g of actinium-226 disintegrates over a period of 145 hours,
how many mg of actinium-226 will remain?
a. 0.3125mg
c. 31.25mg
b. 3.125mg
d. 312.5mg

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.

Determine el momento angular de un rueda de 3000g moviendose a 10m/s con un radio de giro de 400cm

What tightening torque should be used for a hexagonal head screw (not split-bolt) on a 250 kcmil conductor?