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Phys 101 help
5. Superman jumps in front of a speeding bus, puts out his arms and
stops the bus in 1 second. If the bus was traveling at 37 mph and weighs 57000 Lb. What force did Superman apply to the bus? Hints: Use the "Impulse Equation" to relate the average force to the change in momentum in a period of time. For the mass of the bus you use W = m · g which gives m = W / g . Superman applied a force of__________ Lb. (Note English units.) 10. Often in movies you see a person hit by a bullet being thrown backward by the impact of the bullet. If a 69 kg person is hit by a 51 g bullet traveling at 390 m/s what would be the velocity of the person after the bullet hits. Assume the bullet remains in the person. The velocity of the person+bullet is ____________ m/s. Thanks alot for any help ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
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"phanman" wrote in message
... 5. Superman jumps in front of a speeding bus, puts out his arms and stops the bus in 1 second. If the bus was traveling at 37 mph and weighs 57000 Lb. What force did Superman apply to the bus? Hints: Use the "Impulse Equation" to relate the average force to the change in momentum in a period of time. For the mass of the bus you use W = m · g which gives m = W / g . Superman applied a force of__________ Lb. (Note English units.) 10. Often in movies you see a person hit by a bullet being thrown backward by the impact of the bullet. If a 69 kg person is hit by a 51 g bullet traveling at 390 m/s what would be the velocity of the person after the bullet hits. Assume the bullet remains in the person. The velocity of the person+bullet is ____________ m/s. Do your own homework. |
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I'm not above a few hints:
5. Superman jumps in front of a speeding bus, puts out his arms and stops the bus in 1 second. If the bus was traveling at 37 mph and weighs 57000 Lb. What force did Superman apply to the bus? Hints: Use the "Impulse Equation" to relate the average force to the change in momentum in a period of time. For the mass of the bus you use W = m · g which gives m = W / g . Superman applied a force of__________ Lb. (Note English units.) Use F=ma. You can figure out the acceleration. Two things to be careful of. Watch the gravity term and make sure your units are consistant. 10. Often in movies you see a person hit by a bullet being thrown backward by the impact of the bullet. If a 69 kg person is hit by a 51 g bullet traveling at 390 m/s what would be the velocity of the person after the bullet hits. Assume the bullet remains in the person. The velocity of the person+bullet is ____________ m/s. Thanks alot for any help You could use F=ma again, but I'd use conservation of momentum. Again, watch your units. |
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"Edward Smith" wrote in message ... I'm not above a few hints: 5. Superman jumps in front of a speeding bus, puts out his arms and stops the bus in 1 second. If the bus was traveling at 37 mph and weighs 57000 Lb. What force did Superman apply to the bus? Hints: Use the "Impulse Equation" to relate the average force to the change in momentum in a period of time. For the mass of the bus you use W = m · g which gives m = W / g . Superman applied a force of__________ Lb. (Note English units.) You know, in England - physicists use sensible units these days. Use F=ma. You can figure out the acceleration. Two things to be careful of. Watch the gravity term and make sure your units are consistant. The bus is going at about 16 m/s and the bus is about 20,000 kg. a is 16 m/s in a second. So, thats 320,000N |
#5
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"Edward Smith" wrote in message .. . I'm not above a few hints: 5. Superman jumps in front of a speeding bus, puts out his arms and stops the bus in 1 second. If the bus was traveling at 37 mph and weighs 57000 Lb. What force did Superman apply to the bus? Hints: Use the "Impulse Equation" to relate the average force to the change in momentum in a period of time. For the mass of the bus you use W = m · g which gives m = W / g . Superman applied a force of__________ Lb. (Note English units.) You know, in England - physicists use sensible units these days. Use F=ma. You can figure out the acceleration. Two things to be careful of. Watch the gravity term and make sure your units are consistant. The bus is going at about 16 m/s and the bus is about 20,000 kg. a is 16 m/s in a second. So, thats 320,000N I got through some college classes this way. Step 1: Convert to Metric. Step 2: Solve Problem. Step 3: Convert back. MUCH easier. |
#6
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"Edward Smith" wrote in message ... "Edward Smith" wrote in message .. . I'm not above a few hints: 5. Superman jumps in front of a speeding bus, puts out his arms and stops the bus in 1 second. If the bus was traveling at 37 mph and weighs 57000 Lb. What force did Superman apply to the bus? Hints: Use the "Impulse Equation" to relate the average force to the change in momentum in a period of time. For the mass of the bus you use W = m · g which gives m = W / g . Superman applied a force of__________ Lb. (Note English units.) You know, in England - physicists use sensible units these days. Use F=ma. You can figure out the acceleration. Two things to be careful of. Watch the gravity term and make sure your units are consistant. The bus is going at about 16 m/s and the bus is about 20,000 kg. a is 16 m/s in a second. So, thats 320,000N I got through some college classes this way. Step 1: Convert to Metric. Step 2: Solve Problem. Step 3: Convert back. MUCH easier. hopefully you don't do calcs for mars landers like that. |
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