Question

4. Consider your answer to the previous problem (part a). Assume m1 = 4.00 kg, m2 = 2.00 kg and the pulley has a radius of R = 6.00 cm and a mass M = 3.00 kg. The magnitude of the frictional torque exerted on the pulley is 0.500 N.m. (a) Starting from rest, how long does it take for the 4.00 kg block to reach the floor, which is 1.0 meters away? Show all work. (b) How many rotations does the pulley undergo in that time? Show all work. (c) Say that the resistive torque increases with angular speed, such that the time-varying resistive torque is given in Nim by tf = (0.75 t), where t is time in seconds. In this case, how long would it take the 4.00 kg block to hit the ground, if it starts from rest at t = 0 and the floor is still 1.0 meters away? (If you get to a cubic equation and can't solve it, see the note in the answer below.) (d) Is the acceleration pointing in the a: 1.15 s b: 2.6 revolutions c: 1.30 s (Note: You can use Wolfram Alpha - wolframalpha.com - to do difficult calculations, like finding the root of a cubic equation. Type in something like “Solve 3t^3 – 2t^2 +2 = 0" and then hit enter. After the exact answers appear, hit the “approximate forms” button to get the decimal version. Determine which root is the one that is physically meaningful to this problem.)
I need the answer for QUESTION 4 not 3.

Answer 1

yo Since aciteration is wiform and given by a= mg-mag - 2 / M + m, + m2 peeting values, A=448-87-12719.2)-Torbita 1-502m/? 3 자 2 + 4 + 2 Motion from law of s = att fat? (1) ot - (1.502) 4? ta t=2 1.502 t = 1.154 sec. Angular acceleration Idea R 6x10² se Rotational of motion & 키 -25.04 rad) sec? o = loet? O = wit that? = 0 = [ (25.04) [1.154) a rev 27 rad So 0 - 2065 veld

Smce 2 velocity If R s Put a- do व Cheuning) all values and put (7.5) = 2x9.8 - 0.75t 606 2. 613 - 1.6671 a- du dt 2613 -1.667F = 2.6138t-1-667144 € V-2..613 - 1.66762 वड dt २ - 2.6131 - 1.667 12 it 5- 2. 61342 1667 43 हा -Put s=1m 6 equation becomes : S 2 -- 0.277843 - 1 = -Since Resistive forces is increasing then time taken in crease. 431-30 Sec