20. The change in isotopes over time due to the emission of radioactive particles is known as

A. absolute-age dating.

B. radioactive decay.

C. half-life.

D. radiometric dating.

Robotic spacecraft have different levels of complexity, which contributes to overall cost. Which of the following types of missions are likely to be the cheapest?

A narrow beam of light containing orange (610 nm) and blue (470 nm) wavelengths goes from polystyrene to air, striking the surface at a 28.5° incident angle. What is the angle (in degrees) between the colors when they emerge?

If 41.5 mol of an ideal gas occupies 86.5 L at 27.00 °C, what is the pressure of the gas?

Which of the following is not projectile motion? A. A juggler throws a bean bag directly upwards with a velocity of 15 m/s. B. A kickball has the same horizontal velocity when it is kicked and when it lands. C.

A man pushes a box of 40kg up incline of 15°, if the man applies a horizontal force of 200N and the box moves up the plane a distance of 20m at a constant velocity and the coefficient of friction is 0.1, find work done against friction

What causes day and night on earth?

A yo-yo can be thought of as a solid cylinder of mass m and radius r that has a light string wrapped around its circumference (see below). One end of the string is held fixed in space.

Why is time an independent variable and position is a dependent variable in a position versus time graph

A geologist estimates that a large boulder weighs 7840 N. What should he estimate the mass of this boulder to be? A. 650 kg B. 740 kg C. 780 kg D. 800 kg

Two objects have the same momentum. Do the velocities of these objects necessarily have (a) the same directions and (b) the same magnitudes? Give your reasoning in each case.