Question

In the circuit you built last week, you unfortunately made it so the solder (composition 90wt% Pb, 10% Sn) acts as a loadbearing support. Your entire buzzer system has a mass of 15 kg. Given that the lead-tin solder has a tensile strength of 52.5 MPa, an average solder size of 1 mm in diameter, and 3 solder junctions that have a load upon them, will your device fail?

Answer 1

weight = m*g
       = 15*9.8
       = 147 N
     
A = pi*r^2
= pi*(1*10^-3 /2)^2
= 7.854*10^-7 m^2

P on each = 1/3* (weight /Area)
          = 147/(3*7.854*10^-7)
          = 6.24*10^7 Pa
          = 62.4 Mpa
      
tensile strength is 52.5 Mpa

Since applies stress is more than strength, this will fail