Homework Help Forum: physics

Posted by Sandhya on Monday, October 27, 2008 at 5:25am.

You are hired to check the technical validity of a futuristic space mystery production. The scene takes place during the rst manned trip to Pluto's moon, Charon. Sally Skywalker is outside the spaceship repairing some hardware, when her safety line to the spaceship mysteriously breaks. Her thruster pack also is damaged, so she has no obvious means of propul- sion. She is at rest relative to the spaceship, 200 meters away from it, with only 7 minutes of oxygen left in her life support pack. To get back to the ship, she decides to remove her tool kit and throw it away. Assuming that the combined mass of Sally and her spacesuit is 97 kg and the mass of the tool kit is 14 kg, what is the minimum speed that she can throw the tool kit, in order to get back to the spaceship before her oxygen supply is exhausted?

• physics - bobpursley, Monday, October 27, 2008 at 5:32am

  Use conservation of momentum. I will be happy to check your work.

  
  

  • physics - Sandhya, Monday, October 27, 2008 at 6:20am

    Initial momentum = 0 Velocity with which skywalker should mve before oxygen exhausts = u = 200/7*60 = 0.48 m/s Velocity of throw of kit = v Mass of skywalker = M = 97 kg Mass of kit =m = 14 kg Final momentum = Mu + mv = 97*0.48 + 14v v = 97*0.48/14 = 0.016 m/s Is my working correct?

    
    

• physics - drwls, Monday, October 27, 2008 at 6:29am

  7 min = 420 s. She needs to acquire a velocity towards the ship of 200m/420s = 0.48 m/s 0.48*97 = 14 v v = 3.3 m/s Right formula, wrong arithmetic

  
  

  • physics - Sandhya, Monday, October 27, 2008 at 6:41am

    Thanks a lot for pointing out the arithmetic mistake.

    
    

Answer this Question

First Name:
School Subject:
Answer: