John Carter, really?

Classical Mechanics Level 1

A few years ago, a movie came out about a soldier, John Carter, who was transported to Mars and could perform amazing feats of strength and jumping due to the lower Martian gravity. The surface gravity of Mars is 0.38 times that of Earth. If John could lift $100\text{ kg}$ on Earth (about right for a decently in shape and athletic person), how much mass (in $\text{kg}$ ) could he lift on Mars?

263.16 380 26.31 38

1 solution

David Mattingly Staff
May 13, 2014

To lift a mass, John needs to exert a force equal to the gravitational force on the mass, which is $mg$ . Since the force John can exert is the same on earth or Mars, we therefore have $m_e g_e=m_m g_m$ . This yields that the mass he can lift on Mars is $100 g_e/g_m=100/0.38=263.16~kg$ .

John Carter, really?

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