Mechanical advantage of a machine is the ratio of the output force over the input force or M=Fo/Fi. Since M=1, Fi=Fo, or the input force is equal to the output force. This means that to raise the refrigerator that weighs 900 N, we need the same input force of 900 N, or Fo=Fi=900 N.
No force is required to lift that balloon. In fact, force is required to hold it down, and if you let go, it's up, up, and away.
Since the balloon's density is less than the density of the air around it, it's lighter than the air it displaces, there is a net upward buoyant force acting on it, and it floats up !
d.) a and b only
This is because sound needs a medium to travel. It can travel in a solid (the fastest) and air for example. Sound waves cannot propagate through a vacuum and since space is a vacuum the answer is a and b only.
Answer:
not sure just need points
Explanation:
a+b+c
