Suppose you have 50 grams of a radioactive isotope with a half-life of 2 years. how much of the isotope will you have after 4 years?
a. 50 g
b. 25 g
c. 12.5 g
d. 6.25 g

Which surface feature of the moon is characterized by mountainous areas? terrae craters maria regolith

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 790 n/m. it is initially at rest on an inclined plane that is at an angle of 28 degrees with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is k = 0.14. in the initial position, where the spring is compressed by a distance of a = 0.18 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Aphysical change is a change in the size, shape,, or stafe of matter true or false