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I know this question has been asked before, but what I don't understand wasn't addressed. Any insight is greatly appreciated!
Here was the question:
Tom, who has a mass of 80 kg, and Mary, who has a mass of 50 kg, jump off a 20-m tall building and land on a fire net. The net compresses and they bounce back at the same time. Which of the following is not true?
A. Mary will bounce higher than Tom.
B. Tom's change of momentum= 3,200 kg m/s.
C. Tom will experience a greater force upon impact than Mary.
D. The energy in this event is concerted from potential to kinetic to elastic to kinetic.
My thinking was when they hit the net their kinetic energy is eventually all converted into the potential energy of the spring. Since they hit the net together they would both end up at the same displacement, and would thus have equal energy: 1/2kx^2. Then this would get converted again to equal amounts of kinetic energy, and then potential energy for each of them separately. But since Tom is heavier, in order for him to have the same amount of kinetic energy as Mary, his velocity leaving the net must be less, and then he would end up at a lower height.
The answer should be A... can anyone tell me what's wrong here?
Here was the question:
Tom, who has a mass of 80 kg, and Mary, who has a mass of 50 kg, jump off a 20-m tall building and land on a fire net. The net compresses and they bounce back at the same time. Which of the following is not true?
A. Mary will bounce higher than Tom.
B. Tom's change of momentum= 3,200 kg m/s.
C. Tom will experience a greater force upon impact than Mary.
D. The energy in this event is concerted from potential to kinetic to elastic to kinetic.
My thinking was when they hit the net their kinetic energy is eventually all converted into the potential energy of the spring. Since they hit the net together they would both end up at the same displacement, and would thus have equal energy: 1/2kx^2. Then this would get converted again to equal amounts of kinetic energy, and then potential energy for each of them separately. But since Tom is heavier, in order for him to have the same amount of kinetic energy as Mary, his velocity leaving the net must be less, and then he would end up at a lower height.
The answer should be A... can anyone tell me what's wrong here?
