Answer: Velocity of 3m is the faster
Explanation: Velocity of 3m is the faster because velocity of -4m goes in an opposite direction to positive velocities
Answer: "The groups had evolved into separate species. "
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Potential energy due to gravity = Ep = mgh [symbols have their usual meaning ]
Evidently, HALVING the mass will make Ep , HALF its previous value. So, It will be halved.