Energy is passed from organisms at one trophic level to organisms in the next trophic level. ... Energy is an open system: flows from the sun to the earth and then out for the earth as heat. What is a trophic level? The feeding positions in a food chain or web are called trophic levels
Answer:
0.07142 m/s in the opposite direction of the bullet
Explanation:
= Mass of rifle = 70 kg
= Mass of bullet = 0.01 kg
= Velocity of rifle
= Velocity of bullet = 500 m/s
As the momentum of the system is conserved

The recoil velocity of the rifle is -0.07142 m/s
The negative sign shows the opposite direction of the rifle.
Answer:Due to the pressure difference created by rotating fans.
Explanation:
In most of the vacuum cleaners, there is an area which is of disc shape and it is in right next to the motor. There are several fans within the disc that spin at a very high velocity.
The blades will push the air outside of the disk.There is no air in inside of the disc and air pressure creates which pushes air inside the disk to replace the missing air.
So motor is pushing the air outside and to maintain this pressure the air is pushing toward inside with dirt.