What is your question exactly? I'm confused?
Answer:
is the rock's speed.
Explanation:
Momentum is defined as motion possessed by the moving body's mass. Mathematically it a product of mas and velocity of the body.

Given : Mass of rock = m = 1.45 kg
Velocity of the rock = v
Momentum of the rock = P =


is the rock's speed.
Answer:
quantity A is mass and quantity B is wright
When plants die they become food for the decomposer for example Lettuce, If all the Lettuce in someones field died the decomposer would get its nutriets and make the soil stronger, so if you plant more Lettuce and it survives the Consumer would get to eat the lettuce. Hope this helped! :)