Can you help with these 2 Long Questions? and provide me with the equations The
ID: 1860882 • Letter: C
Question
Can you help with these 2 Long Questions? and provide me with the equations
The belt sander shown in Fig. P2.35 has a belt speed of 1500 ft/min. The coefficient of friction between the sander and a plywood surface being finished is 0.2. If the downward (normal) force on the sander is 15 lbf. determine (a) the power transmitted by the belt, in Btu/s and hp, and (b) the work done in one minute of sanding, in Btu. Fig. P2.35 Air contained within a piston-cylinder assembly undergoes three processes in series: Compression at constant pressure from p1 = 10 lbf/in.2, V1 = 4 ft3 to state 2. Constant-volume heating to state 3, where p3 = 50 bf/in.2 Expansion to the initial state, during which the pressure-volume relationship is pV = constant. Sketch the processes in series on p-V coordinates. Evaluate (a) the volume at state 2, in ft3, and (b) the work for each process, in Btu.Explanation / Answer
Fric force = 0.2*15 = 3 lbf
a) Power = F*v = 3*1500/60 = 75 ft-lb/s
1 ft-lb = 0.00129 Btu
Power = 75*0.00129 = 0.0963 Btu/s
1 Btu/min = 0.0236 hp
Power = 0.0963*60*0.0236 = 0.136 hp
b) Work done = 0.0963*60 = 5.778 Btu
2.34
P1*V1 = P3*V3
10*4 = 50*V3
V3 = 0.8 ft^3
V2 = V3 = 0.8 ft^3
W1-2 = P1*(V2 - V1)= (10*12^2) *(0.8 - 4) = -4608 ft-lb = -4608*0.00129 Btu = -5.94 Btu
W2-3 = 0 (constant volume)
W3-1 = P3*V3 ln (V1 / V3) = (50*12^2)*0.8 ln (4 / 0.8) = 9270.4 ft-lb = 9270.4*0.00129 Btu = 11.96 Btu