3.Rokiah taking 3 minutes to walk to the sundry shop located 400 m to the right of
her house After I minute, she buys an ice cream
and walks to the playground located 300 m from
the sundry shop in 2 minutes. She sits and rests on
a bench near the playground for 2 minutes. Then,
using a shortcut to return to her house, Rokiah
reaches ber house in 2 minutes.
(a) What is the average velocity of the motion of
Rokiah from
(i) house to the sundry shop?
(ii) sundry shop to the playground?
(iii) playground to the house?
(b) Calculate Rokiah's average speed
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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)