UJI BEBAN KERJA TERHADAP KINERJA ALAT PENUMBUK MEKANIS (Test of The Effect of Workload on Performance of Mechanical Pestle) - Yanti, Ermida; Program Studi Keteknikan Pertanian Fakultas Pertanian Jl. Prof. Dr. A. Sofyan No. 3 Kampus USU Medan 20155 (Universitas Sumatera Utara, 2018)