Answer:
The two objects will collide with the same position vector for all three components at exactly t = 4 s
Explanation:
For two particles starting out at the same time to collide, their position Vector's at the time of collision must be exactly the same.
So, at the collision point, position vector of object 1 is equated to that of object 2.
r₁ = (t², 13t-36, t²)
r₂ = (7t-12, t², 5t-4)
At he point of collision
t² = 7t - 12
t² - 7t + 12 = 0
t² - 4t - 3t + 12 = 0
t(t - 4) - 3(t - 4) = 0
t = 3s or t = 4s
13t - 36 = t²
t² - 13t + 36 = 0
t² - 4t - 9t + 36 = 0
t(t - 4) - 9(t - 4) = 0
t = 9s or 4s
t² = 5t - 4
t² - 5t + 4 = 0
t² - 4t - t + 4 = 0
t(t - 4) - 1(t - 4) = 0
t = 1s or t = 4s
The three components intersect at other times, but at t = 4s, they all intersect at the same time! Meaning that, at this point the two objects are at the same place with the same position vector at that time.
The whistle you use to call has a frequency of 21 kHz, so you do not recognize it also because your threshold of hearing is only 20 kHz. Since you are unable to hear sounds above this value, you request your friend to blow the whistle and move farther away. The frequency will decrease due to Doppler effect.
Answer:
b. the Paleozoic Era
Explanation:
The first vertebrates to appear are primitive fish in the Cambrian Period, but bony fishes with actual bony vertebratae didn't appear for another 100 million years. The Cambrian Period is the first of three periods in the Paleozoic Era. The Cambrian explosion was an event when practically all major animal phyla started appearing in the fossil record.
Answer:
organisms eat food because they will die if they don't, just like us humans. their bodies wont be able to run if they do not have a energy supply. the energy supply for every organism is food. this is why organisms eat food.
