Question

.

A student holds two pieces of paper at the top, 10 cm apart. The flat sides of the papers face each other.

What happens when the student uses a straw to blow a stream of air between the papers?


Lower pressure causes the papers to move farther apart.

Lower pressure causes the papers to move closer to each other.

Higher pressure causes the papers to move farther apart.

Higher pressure causes the papers to move closer to each other.

Answer 1

higher the pressure the air would spread apart causing the paper to move to the other side. So higher pressure causes the papers to move farther apart.

Answer 2

Lower pressure causes the papers to move closer to each other.

Step-by-step explanation:

As we know by Bernoulli's principle

`P + (1)/(2)\rho v^2 = constant`

so here when air between the two papers is at normal situation then let say the pressure between the two papers is
`P_o`

now if the air between two papers is blown by straw then the speed of air between two papers will increase.

So as per the equation above the pressure will decrease as the sum of pressure and kinetic energy per unit volume must be constant.

So here the pressure between two papers will decrease due to which the two papers will come closer to each other.

so correct answer will be

Lower pressure causes the papers to move closer to each other.