Question

I need the answers for # 5 and #8

2) m m mi Now, three masses m, = 4.8 kg, m2 = 14.4 kg and m2 = 9.6 kg hang from three identical springs in a motionless elevator. The springs all have the same spring constant that you just calculated above. What is the force the top spring exerts on the top mass? 282.64 N Submit + 3) What is the distance the lower spring is stretched from its equilibrium length? 22 cm Submit 4) Now the elevator is moving downward with a velocity of v = -2.8 m/s but accelerating upward with an acceleration of a = 4.9 m/s2. (Note: an upward acceleration when the elevator is moving down means the elevator is slowing down.) What is the force the bottom spring exerts on the bottom mass? 140.16 N Submit 5) What is the distance the upper spring is extended from its unstretched length? cm Submit

Answer 1

from the previous parts,

spring constant of the springs, k = m3*g/x

= 9.6*9.8/0.22

= 427.6 N/m

5) extension of the upper string, x = (m1 + m2 + m3)*(g + a)/k

= (4.8 + 14.4 + 9.6)*(9.8 + 4.9)/427.6

= 0.990 m

= 99.0 cm <<<<<<<<<--------------Answer

6) speeding up <<<<<<<<<--------------Answer

7) x1 > x2 > x3 <<<<<<<<<--------------Answer

8) Extension of the middle spring,

x = (m2 + m3)*(g + a)/k

= (14.4 + 9.6)*(9.8 - 1.8)/427.6

= 0.449 m

= 44.9 cm <<<<<<<<<--------------Answer