a 90 kg astronaut floating in space is carrying a 1 kg camera and a 10 kg baatter pack.
he hurls the camera out into space at 15 m/s and throws the battery at 10 m/s in the same direction. What's the resulting increase inhis speed after each throw?


would I have to use the impulse or momentum equation for this? And would I be able to solve this in one equation or will I have to use a couple. Any directions on how to start the problem would be greatly appreciated. Thanks!

You would use conservation of momentum for these problems. One equation for each of the two throws to find the astronaut's change of velocity. Don't forget that the astronaut has the battery pack still with him when he throws the camera, so his total mass at that point is 90+10kg. Hope this helps.

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Originally Posted by ebaines

You would use conservation of momentum for these problems. One equation for each of the two throws to find the astronaut's change of velocity. Don't forget that the astronaut has the battery pack still with him when he throws the camera, so his total mass at that point is 90+10kg. Hope this helps.

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Hey there ebaines I am having troubles with the question as well after reading it. Wouldn't we consider total momentum before hand to be zero? or am I just plain wrong... help!

Yes- initial momentum is zero, and so is final momentum. Remember that the velocities of the astronaut and camera or toolbag are in opposite directions - so consider one to be negative and the other positive. Hence when the astronaut throws the camera you have:



where and are the mass and velocity of the astronaut/battery and and are the mass and velocity of the camera. You know all the values here except for , which you can now solve for. Hope this helps.