Answer to Question #306984 in Mechanics | Relativity for Nica

Question

a. An astronaut has a mass of 70 kg when measured on Earth. What is her weight in deep space, far from any celestial body? What is her mass there?

b. Here is a story of a horse and a farmer: One day, the farmer attaches a heavy cart to the horse and demands that the horse pull the cart. “Well,” says the horse, “I cannot pull the cart, because, according to Newton’s third law, if I apply a force to the cart, the cart will apply an equal and opposite force on me. The net result will be that I cannot pull the cart, since all the forces will cancel. Therefore, it is impossible for me to pull this cart.” The farmer was very upset! What could he say to persuade the horse to move?

Answer 1

a)

Weight is zero, mass is constant (70 kg).

b)

The horse should pull a cart much stronger.