Make sure your calculator is set to DEGREES and not RADIANS when performing your sinθ calculation.
sin(10) = -0.54402
sin(10°) = 0.17365
You could also try using trig tables if you're unsure how to do this.
So:
2500sin(10°) = 434 lb
describes a circle of radius 2 centered at (0,2). A revolution of this region about the y-axis would give you a sphere of radius 2, so the volume would be .