Answer:
Distance: 21 yd, displacement: 15 yd, gain in the play: 12 yd
Explanation:
The distance travelled by Sam is just the sum of the length of each part of Sam's motion, regardless of the direction. Initially, Sam run from the 3 yd line to the 15 yd line, so (15-3)=12 yd. Then, he run also 9 yd to the right. Therefore, the total distance is
d = 12 + 9 = 21 yd
The displacement instead is a vector connecting the starting point with the final point of the motion. Sam run first 12 yd straight ahead and then 9 yd to the right; these two motions are perpendicular to each other, so we can find the displacement simply by using Pythagorean's theorem:

Finally, the yards gained by Sam in the play are simply given by the distance covered along the forward-backward direction only. Since Sam only run from the 3 yd line to the 15 yd line along this direction, then the gain in this play was
d = 15 - 3 = 12 yd
Answer:
The first flowering plants appeared in the Mesozoic era, not the Paleozoic era.
Explanation:
The Mesozoic era was an era where numerous organisms started to develop in very unique and more advanced ways, both the animals and the plants. In the last period of the Mesozoic, the Cretaceous, the first flowering plants started to appear on the scene. This was revolutionary trait of the plants, and soon these plants started to occupy more and more space and became one of the dominant organisms on the planet. Other important evolution that took place in this period are the appearance of the dinosaurs and the mammals, both becoming the dominant animals on the planet, first the dinosaurs, after that the mammals.
Use the impulse-momentum theorem.

Substitute your known values:

Hope this helps!