Electromagnetic waves and astronaut

In summary, a spacewalking astronaut with a mass of 150kg, floating 20.0 m from a space shuttle with zero velocity, needs to use a 220w flashlight as a "light rocket" to reach the shuttle. Using the equation E=c*p, with E as the energy of the light beam, p as its momentum, and c as the speed of light, the astronaut initially calculated a time of 1250000 hours. After correcting for units and using the formula d=(1/2)*a*t^2, the correct time is determined to be 25.1 hours.
  • #1
yogi41
6
0

Homework Statement



I've been trying to do this problem for about 2 hours now. I can't seem to find the right equations to use. Any help would be appreciated

A spacewalking astronaut servicing an orbiting space telescope has run out of fuel for her jet pack and is floating 20.0 m from the space shuttle with zero velocity relative to the shuttle. The astronaut and all her gear have a total mass of 150kg. If she uses her 220w flashlight as a "light rocket," how long will it take her to reach the shuttle?

Homework Equations





The Attempt at a Solution

 
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  • #2
How about this one, E=c*p. Where E is the energy of the light beam, p is it's momentum and c=speed of light.
 
  • #3
the answer is supposed to be 25.1 hours. When i used E=c*p i ended up getting 1250000 hours. Am i doing a simple calculation wrong?
 
  • #4
I get the 25 hour figure as well. Did you compute the force exerted by the beam? What are some of your intermediate results?
 
  • #5
well i first calculated p 220w/3x10^8 which was 7.33 x 10^-7
then i divided that answer by 150kg to get 4.89 x 10^-9 which I'm assuming is my velocity
from there i divided the distance from the ship which was 20m to get 2.44 x 10^-10
and then i divided 1/2.44 x 10^-10 to get my answer in seconds
 
  • #6
Keep track of units. Then you won't have to 'assume' that something is a velocity. Power/c is a force. (Power/c)/mass is an acceleration. Not a velocity.
 
Last edited:
  • #7
so I took the square root of the 2.44 x 10^-10 1/s^2 to get 1.56 x 10^-5 1/s and i flipped the sign by 1/1.56 x 10^-5 1/s to get 64018.4 but then when i convert it back to hours it's only 17.8 hours when it is supposed to be 25.1 hours. Where did i make the mistake? thanks for the help
 
  • #8
The relation between distance, time and acceleration is d=(1/2)*a*t^2. Looks like you dropped the (1/2).
 

1. What are electromagnetic waves?

Electromagnetic waves are a type of energy that is created when an electric field and a magnetic field interact. These waves travel through space at the speed of light and can be categorized based on their frequency and wavelength.

2. How are electromagnetic waves used in space exploration?

Electromagnetic waves are used in space exploration for communication, navigation, and imaging. They allow astronauts and spacecrafts to send and receive signals, as well as capture images of distant objects.

3. Can astronauts be harmed by electromagnetic waves?

Yes, astronauts can be harmed by certain types of electromagnetic waves, such as high-frequency radiation. However, NASA has strict safety guidelines in place to protect astronauts from harmful exposure.

4. How do astronauts protect themselves from electromagnetic waves in space?

Astronauts protect themselves from electromagnetic waves by wearing specialized suits and using shielded equipment. They also limit their exposure to certain types of radiation and monitor their health closely during space missions.

5. Are there any benefits of electromagnetic waves for astronauts?

Yes, there are several benefits of electromagnetic waves for astronauts. They allow for reliable communication and navigation in space, as well as the ability to study and gather data about the universe. Electromagnetic waves also play a crucial role in the technology used in space exploration.

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