Cho hệ số cơ như hình 5 thanh m chuyển động thẳng đứng nhờ khe cô định. Khối lượng thận và nêm là m=M=1kg, a = 30° lấy g = 10m/s^2. Bỏ qua mọi ma sát. Tìm gia tốc của nêm M

Julia would be observing a. static electricity was caused by her sweater rubbing against her shirt and transferring electrons. she didn't touch anything metal, so that would cancel out b.she most likely didn't rub her sweater against her hair either, so that cancels out c.she also didn't scoot across the carpet while trying to take her sweater off, that cancels out d.so that leaves a.a. is correct.