The half-life of radium 226 is 1600 years it decays into radon-222 what fraction of the original amount of radium-226 in a sample will still be radium after 8000 years. A. 1/32
B. 1/8
C. 1/16
D. 1/4

To practice problem-solving strategy 10.1 for energy conservation problems. a sled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slides a distance d1 down the slope and then covers the distance d2 along the horizontal terrain before stopping. find the coefficient of kinetic friction μk between the sled and the ground, assuming that it is constant throughout the trip.