Physics

Problem

Two students stand facing each other on frictionless ice. Student A has mass

50\,\text{kg}

and student B has mass

70\,\text{kg}

. They push each other apart so that student A moves backwards with an acceleration of

6\,\text{m}\,\text{s}^{-2}

. Which statement is correct? a) Student B experiences a force of

420\,\text{N}

opposite to that on A, and therefore accelerates at

6\,\text{m}\,\text{s}^{-2}

. b) Student B experiences a force larger than

300\,\text{N}

because her mass is greater. c) Student B experiences a force of

300\,\text{N}

in the opposite direction, and the net external force on the two-student system is zero. d) Both students accelerate equally because the internal action–reaction forces cancel on the system.

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