Referring to the figure shown, identify the true statements about the characteristics of the hydraulic grade line (HGL) and energy grade line (EGL) from the following. (Check all that apply.)Group of answer choicesThe gage pressure of a fluid is zero at locations where the HGL intersects the fluid.At a pipe exit, the pressure head is zero (atmospheric pressure), and thus the HGL coincides with the pipe outlet.The EGL is always a distance V^2/2g above the HGL.For stationary bodies such as reservoirs or lakes, the EGL and HGL coincide with the free surface liquid.The mechanical energy loss due to frictional effects causes the EGL and HGL to slope upward in the direction of flow.For open-channel flow, the EGL and HGL coincide with the free surface of the liquid.In an idealised Bernoulli-type flow, EGL is horizontal and its height remains constant.A steep increase occurs in EGL and HGL whenever mechanical energy is removed from the fluid.

The true statements about the characteristics of the hydraulic grade line (HGL) and energy grade line (EGL) are:

1. The gage pressure of a fluid is zero at locations where the HGL intersects the fluid. This is because the HGL represents the total head available to the fluid at a particular point, which includes the pressure head. If the HGL intersects the fluid, it means the pressure head is zero, hence the gage pressure is zero.

2. At a pipe exit, the pressure head is zero (atmospheric pressure), and thus the HGL coincides with the pipe outlet. This is because at the pipe exit, the fluid is exposed to the atmosphere, hence the pressure is atmospheric pressure, which is considered as zero in gage pressure terms.

3. The EGL is always a distance V^2/2g above the HGL. This is because the EGL represents the total energy head available to the fluid, which includes the kinetic energy head (V^2/2g) in addition to the pressure head and potential energy head (which are represented by the HGL).

4. For stationary bodies such as reservoirs or lakes, the EGL and HGL coincide with the free surface liquid. This is because for stationary bodies, there is no kinetic energy head, hence the EGL and HGL are equal and coincide with the free surface.

5. The mechanical energy loss due to frictional effects causes the EGL and HGL to slope downward in the direction of flow, not upward. This is because frictional losses reduce the total energy available to the fluid, hence reducing the EGL and HGL.

6. For open-channel flow, the EGL and HGL coincide with the free surface of the liquid. This is because in open-channel flow, the fluid is exposed to the atmosphere, hence the pressure head is zero and the EGL and HGL coincide with the free surface.

7. In an idealised Bernoulli-type flow, EGL is horizontal and its height remains constant. This is because in Bernoulli-type flow, there are no