Its the fourth one hope i helped
Answer:
Unbalanced force
Explanation:
According to Newton's second law of motion, any unbalanced force that is applied on a body will cause it to have some acceleration.
However, If the force is balanced like the net effect of one force is cancelled by the other, it will result in total force as zero, that will cause zero acceleration in the body.
Newton's second law of motion states:
F=ma
where m is mass and a is acceleration, so it means that is any of these factors is zero , the force will be zero, and hence force is zero only when it is cancelled by some force acting in opposite direction.
For example: When person is dragging the table with a force of 30 N on left side, while the other person is dragging the same table with same force on right side. The table will have zero acceleration.
Hope it help!
The particles vibrate but they are tight together so they don’t move past each other
To breath in the air, frog lowers the floor of the mouth. That causes throat to expand and nostrils to open. The air enters the mouth through nostrils and after that nostrils close. The floor of the mouth contracts to push the air into the lungs. To breath out the air, the floor of the mouth is lowered again and the air is pushed into the mouth. Nostrils open again and the air leaves the mouth.
Because its a main part of it .
