Match the electrocardiogram component with its expected finding.  Each option is only used once. 

Suppose we imagine the Sun to be about the size of a grapefruit. Which of the following describes the size and distance of Earth on the same scale?

Suppose that two objects collide. Which of the following things is not the same both before and after the collision?

In the formula E = mc 2, what does E represent?

The acceleration of gravity on Earth is approximately 10 m/s 2 (more precisely, 9.8 m/s 2). If you drop a rock from a tall building, about how fast will it be falling after 3 seconds?

The number of stars in the Milky Way Galaxy is approximately

Modern telescopes are capable of seeing bright galaxies up to about

Grass appears green because

The escape velocity from Earth is greater for larger rockets than for small ones.

If we observe one edge of a star to be redshifted and the opposite edge to be blueshifted, what can we conclude about the star?