The diagram below shows an orange M with mass $0.14$ kg moving at $4.0$ ms$^{-1}$ and an orange N with mass $0.25$ kg moving at $3.5$ ms$^{-1}$ .

The diagram also defines the coordinate system to use for this problem.

<pii-diagram data='{"width":300,"height":200,"elements":[{"type":"axes","x":225,"y":80,"xLength":45,"yLength":45,"xLabel":"x","yLabel":"y"},{"type":"icon","kind":"orange","x":33.91474184782601,"y":44.73675271739131,"size":30,"label":""},{"type":"icon","kind":"orange","x":216.2296195652175,"y":138.17849864130432,"size":30,"label":""},{"type":"arrow","x1":202.7921195652175,"y1":140.93834918478262,"x2":82.79211956521749,"y2":140.93834918478262,"label":""},{"type":"arrow","x1":34.61786684782601,"y1":58.77717391304341,"x2":82.88468070652152,"y2":141.55400815217376,"label":""},{"type":"label","x":216.37822690217376,"y":167.74116847826087,"text":"N","anchor":"middle","fontWeight":"bold","stroke":"black"},{"type":"label","x":75.90438179347825,"y":38.0740489130435,"text":"M","anchor":"middle","fontWeight":"bold","stroke":"black"},{"type":"label","x":74.87262228260852,"y":55.2080502717391,"text":"0.14 kg","anchor":"middle","stroke":"bold"},{"type":"label","x":218.46297554347848,"y":186.37398097826082,"text":"0.25 kg","anchor":"middle","fontWeight":"","stroke":"black"},{"type":"label","x":83.95040760869506,"y":88.93512228260869,"text":"4.0 m/s","anchor":"middle","stroke":"black"},{"type":"label","x":159.91847826086928,"y":137.02021059782612,"text":"3.5 m/s","anchor":"middle","stroke":"black"},{"type":"line","x1":35.2462635869565,"y1":127.54755434782606,"x2":35.2462635869565,"y2":58.024796195652186,"dash":"2 4"},{"type":"arc","cx":35.21993885869756,"cy":60.185971467391454,"r":30,"startAngle":0,"endAngle":30,"label":"30°","closed":true,"labelOffset":50,"rotation":-90}]}'></pii-diagram>

Orange M and N are sliding on a frictionless surface in an isolated system.

Orange M and N collide and stick together.

What is the velocity of the x component of the combined objects after the collision?