Um tubo sonoro, aberto nas duas extremidades, tem comprimento de 40 cm. Em certo instante o ar dentro do cubo está vibrando em seu 4° harmônico. sendo 340 m/s a velocidade do som no ar, qual é a frequência do som emitido pelo tubo?

a)425 Ghz

b)850 Hz

c)1,275 kHz

d)1,7 kHz

e)2125 Hz

Panel bc in fig. p2.76 is semi-circular, with the 3 meter radius and horizontal straight edge through point b. compute (a) the hydrostatic force of the water on the panel, (b) its center of pressure, and (c) the moment of this force about point b. assume atmospheric pressure on the dry side of the panel

Which of the following is a true statement about the acceleration ~a of the pendulum bob ~a is equal to the acceleration due to gravity. ~a is perpendicular to the bob’s trajectory. ~a is equal to the instantaneous rate of change in velocity. ~a is tangent to the bob’s trajectory.

The radioactive isotope of lead, pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.3 hours. if 1 gram of this isotope is present initially, how long will it take for 80% of the lead to decay? (round your answer to two decimal places.)