Aradioactive isotope of potassium (k) has a half-life of 20 minutes. if a 40.0 gram sample of this isotope is allowed to decay for 80 minutes, how many grams of the radioactive isotope will remain?

a) 2.5 grams
b) 5.0 grams
c) 10.0 grams
d) 40.0 grams

The step-down transformer gives a current of 10a at 24v if the primary voltage is 240v calculate the 1_primary current 2_the power input 3_the power output

The x-coordinate of a particle in curvilinear motion is given by x = 3.1t3 - 4.9t where x is in feet and t is in seconds. the y-component of acceleration in feet per second squared is given by ay = 2.3t. if the particle has y-components y = 0 and vy = 5.0 ft/sec when t = 0, find the magnitudes of the velocity v and acceleration a when t = 1.8 sec. sketch the path for the first 1.8 seconds of motion, and show the velocity and acceleration vectors for t = 1.8 sec. answers: v = ft/sec a = ft/sec2

One form of energy can be another type of energy. a. created to form b. transformed into c. destroyed and then created to form