(b) A gate has rusty hinges that are very still. A man opens the gate by pulling on it, as shown in Fig. 1.1
Fig. 1
After he has passed through the opening, he closes the gate behind him.
When closing the gate, the man pulls it at a point halfway along its length.
State two differences between his force, when closing the gate and his force when he opened
the gate
?
2
[2]

The atoms in a sidewalk on a hot summer day are vibrating the atoms in the sidewalk on a freezing day in winter. a. more rapidly than b. more slowly than c. at the same speed as

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i.e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?