Una mujer de masa m está parada en el borde de una mesa giratoria horizontal de momento de inercia I y radio R. La mesa al principio está en reposo y tiene libertad de moverse alrededor de un eje vertical sin fricción que pasa por su centro. La mujer empieza a caminar alrededor de la orilla en direción de las manecillas del reloj (vista desde arriba) a una velocidad constante v en relación a la Tierra. a) En qué dirección y con qué velocidad angular gira la mesa?

b) Cuál es el trabajo efectuado por la mujer para poner en movimiento la mesa?

The ultracentrifuge is an important tool for separating and analyzing proteins. because of the enormous centripetal accelerations, the centrifuge must be carefully balanced, with each sample matched by a sample of identical mass on the opposite side. any difference in the masses of opposing samples creates a net force on the shaft of the rotor, potentially leading to a catastrophic failure of the apparatus. suppose a scientist makes a slight error in sample preparation and one sample has a mass 10 mg larger than the opposing sample. if the samples are 12 cm from the axis of the rotor and the ultracentrifuge spins at 70,000 rpm, what is the magnitude of the net force on the rotor due to the unbalanced samples? ( be thorough on your answer)

Amagnetic field applies forces on: a)static chargesb)moving chargesc)water flow

Emagnitude of the electrical force acting between a +2.4 ×  10–8  c charge and a +1.8 ×  10–6  c charge that are separated by 0.008 m is    n, rounded to the tenths place.