Ball a is attached to one end of a rigid massless rod, while an identical ball b is attached to the center of the rod, as shown in the figure. each ball has a mass of m =
0.450 kg, and the length of each half of the rod is l = 0.420 m. this arrangement is held by the empty end and is whirled around in a horizontal circle at a constant rate,
so that each ball is in uniform circular motion, ball a travels at a constant speed of va = 5.10 m/s. find (a) the tension of the part between a and b of the rod and (b)
the tension of the part between b and the empty end.

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

Determine el momento angular de un rueda de 3000g moviendose a 10m/s con un radio de giro de 400cm

Aturntable a is built into a stage for use in a theatrical production. it is observed during a rehearsal that a trunk b starts to slide on the turntable 10 s after the turntable begins to rotate. knowing that the trunk undergoes a constant tangential acceleration of 0.31 m/s2, determine the coefficient of static friction between the trunk and the turntable.