Phy201: General Physics I Exam #2-Study Guide 1. Demonstrating a feat of strengt
ID: 1398111 • Letter: P
Question
Phy201: General Physics I Exam #2-Study Guide 1. Demonstrating a feat of strength, a different Joey (45 kg) performs some pull-ups. He attaches his hands to the ends of 2 opposing "mass-less" cables and hangs in place by the cables (as shown in the diagram). The cables are each attached to a heavy block (m1-75 and m2 75 kg) placed on top of the pulley platform. As Joey hangs, the lower portion of each cable is oriented at a 70° angle above the horizontal direction. Summer 2015 NOTE: The blocks are not secured but are held in place by static friction between the platform and each block. What is the magnitude of the tension force in each cable, respectively? i. mi m2 /0 70° Platform 1 Platform 2 ii. The static friction force between block, m, and the platform keeps it from sliding. What is the magnitude of the static friction force acting on mi? iii. Calculate the effective coefficient of static friction (k) for the block, ml.Explanation / Answer
mass of the joey = 45 kg
since he is in equilibrium
let the tension of each rope be T
so
sum of all the vertical forces must be equal to 0
2 * T * sin(70) - mg = 0
2 * T * sin(70) = mg
2 * T * sin(70) = 45 * 9.8
T = 234.651 N
magnitude of tension force on each cable = 234.651 N
for blocks
all the horzontal forces must be equal to 0
frictional force = T
frictional force = 234.651 N
static frictional force between block m1 and platform = 234.651 N