Which statement about the Bernoulli principle and projectile motion is correct?

• A. Pressure is inversely related to velocity.
• B. Lift force occurs due to identical velocity above and below, causing no pressure difference.
• C. Bernoulli principle only applies to solids.
• D. Bernoulli says velocity doesn't affect pressure.

Answer: (A)

In a steady, incompressible flow, slower speeds correspond to higher static pressure and faster speeds correspond to lower static pressure. This inverse relationship is summarized by Bernoulli’s idea that along a streamline, increasing velocity reduces static pressure (P decreases as v increases, assuming height stays the same and viscous losses are negligible).

This helps explain lift: air speeding up over the top surface of a wing lowers the pressure there relative to the slower air beneath, creating an upward lift force. If the velocities on top and bottom were the same, there would be no pressure difference and no lift.

The idea that lift comes from identical velocities on both sides is not correct, and Bernoulli’s principle applies to fluids, not solids. Also, saying velocity doesn’t affect pressure contradicts the principle.