Question

Calculate the gauge pressure of the water gun's reservoir at the instant when it's fired and hits the ground 8.6m away. Assume no initial speed of water in the reservoir, steady water flow, no air resistance, and neglect the height difference between the reservoir and the muzzle.

a. 1.00 atm
b. 3.40 atm
c. 0.50 atm
d. 0.45 atm

Answer 1

The gauge pressure of the water gun's reservoir is equal to the atmospheric pressure.

Step-by-step explanation:

The gauge pressure of the water gun's reservoir can be calculated using the principles of Bernoulli's equation, which states that the pressure at a point in a fluid is equal to the sum of the fluid's static pressure, dynamic pressure, and gravitational potential energy per unit volume. In this case, since the height difference between the reservoir and the muzzle is neglected, we only need to consider the static and dynamic pressure.

The initial speed of water in the reservoir is zero, so the dynamic pressure is also zero. Therefore, the gauge pressure of the water gun's reservoir at the instant when it's fired and hits the ground 8.6m away is equal to the atmospheric pressure, which is 1.00 atm (option a).