(Solved): 2. An object with mass \( m=3 \mathrm{~kg} \) is sliding over a roller coaste ...

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2. An object with mass \( m=3 \mathrm{~kg} \) is sliding over a roller coaster without friction, starting on the left at \( h_{1} \) and sliding to the right to \( h_{4} \), as illustrated in the picture. Gravity is pointing downwards. The heights at the extrema are given by \[ h_{1}=7 \mathrm{~m}, \quad h_{2}=3 \mathrm{~m}, \quad h_{3}=5 \mathrm{~m}, \quad h_{4}=1 \mathrm{~m} \] The initial speed of the object is \( v=1.81 \mathrm{~m} / \mathrm{s} \). Compute the final speed when the object reaches the end of the roller coaster. [4 marks]