I believe it is either A. or C. my guess is A.
Answer:
Population of duck and frog will change with the change
Explanation:
The complete question is
Scientists are studying animals in a large lake area. In this lake area, both owls and raccoons eat ducks, and ducks eat frogs. The data shows that recently the size of the raccoon population decreased. How will the decrease in the raccoon population affect the other populations? Be sure to explain whether the owl population, the duck population, and the frog population will change, and why.
- Owl population will change
-
Duck population will change
-
Frog population will change
Solution
Raccoon eat duck and duck eat frog. Now if the population of Raccoon decreases then the number of predators of duck will decrease thereby increasing the population of duck.
The higher will be the number of ducks, the more frogs they will consume thereby decreasing the population of frogs
Hence both the population of duck and frog will change with the change
Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
Explanation:We have momemtum = mass X velocity
p = mv
OR, p/m = v
v = (125kg m/s)25kg
v = 125/25 m/s
v = 5 m/s
