一物体在水平面上,受恒定的水平拉力和摩擦力作用沿直线运动,已知在第\(1\)秒内合力对物体做的功为\(45J\),在第\(1\)秒末撤去拉力,其\(v-t\)图象如图所示,\(g\)取\(10m/s^{2}\),则\((\) \()\)
进入组卷