The figure shows a sound wave as a function of time when the source is stationary with respect to the observer. An Illustration of a transverse wave and four crests and four troughs are labeled 1 s total.
Which shows the perceived sound wave heard by a stationary observer when the source moves toward the observer?

An illustration of a transverse wave and three crests and three troughs are labeled 1 s total.
An Illustration of a transverse wave that is taller than the previous. Three crests and three troughs are labeled 1 s total.
An Illustration of a transverse wave and four crests and four troughs are labeled 1 s total.
An Illustration of a transverse wave and seven crests and seven troughs are labeled 1 s total.

Part f - example: finding two forces (part i) two dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. the block in (figure 1) has a mass m=10kg and is being pulled by a force f on a table with coefficient of static friction îľs=0.3. four forces act on it: the applied force f (directed î¸=30â above the horizontal). the force of gravity fg=mg (directly down, where g=9.8m/s2). the normal force n (directly up). the force of static friction fs (directly left, opposing any potential motion). if we want to find the size of the force necessary to just barely overcome static friction (in which case fs=îľsn), we use the condition that the sum of the forces in both directions must be 0. using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: fcosî¸â’îľsn=0 fsinî¸+nâ’mg=0 in order to find the magnitude of force f, we have to solve a system of two equations with both f and the normal force n unknown. use the methods we have learned to find an expression for f in terms of m, g, î¸, and îľs (no n).

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

In a good thermo flask the main cause of heat loss is