Patrycia’s overall grade in her physics class is based solely on the average of her scores on 6 unit tests. the grade she received on the first 5 tests are as follows: 89, 93, 95, 92, 90. what grade does patrycia need to earn on her 6th unit test to end up with a 90% in the class?
a.
76.5%
b.
81%
c.
90%
d.
92.5%

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).