24+14 = ____ 37 – 6 =____ 88 – 53 =____ 77 + 12=____
36 – 5 =____ 71 + 7 =____ 23 + 6 =____ 67 – 4 3 =____
40 + 30 – 60 =____ 90 – 80 + 50 =____ 23 + 6 – 11 =____
如图,物体质量为m=2kg,静置于水平面上,它与水平面间的动摩擦因数μ=0.4,用大小为F=10 2 N、方向与水平方向夹角θ=45°的拉力F拉动物体,拉动4s后,撤去拉力F,物体最终停下来.(取g=10m/s2)试求: