A runner is jogging in a straight line at a steady Vr= 4.6 km/hr. When the runner is
L= 3 km from the finish line, a bird begins
flying straight from the runner to the finish
line at vb= 9.2 km/hr (2 times as fast as the
runner). When the bird reaches the finish
line, it turns around and flies directly back to
the runner.
or
finish
line
L
What cumulative distance does the bird
travel? Even though the bird is a dodo, as-
sume that it occupies only one point in space
(a "zero" length bird), travels in a straight
line, and that it can turn without loss of
speed.
Answer in units of km.

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by

Argon, neon, and xenon are examples of