题目

How much did you spend on the apples? (保持原意) 答案：How much did you pay for the apples?（6分）如图所示，斜面倾角θ=30°，物体重G=100N，与斜面间的动摩擦因数为μ=0.2，用平行于斜面向上的拉力F拉物体使其沿斜面向上匀速运动，求拉力F的大小。