Astronaut traveling at constant speed, throws a wrench

[dmitriylm]

1)Homework Statement
An astronaut of mass 82.0 kg is taking a space walk to work on the International Space Station. Because of a malfunction with the booster rockets on his spacesuit, he finds himself drifting away from the station with a constant speed of 0.600 m/s. With the booster rockets no longer working, the only way for him to return to the station is to throw the 7.20 kg wrench he is holding.

1)In which direction should he throw the wrench?
-Away from the station
-Towards the station

2)He throws the wrench with speed 18.58 m/s with respect to himself.
After he throws the wrench, how fast is the astronaut drifting toward the space station?

3)What is the speed of the wrench with respect to the space station?
3Your answer is incorrect.

Homework Equations

MV = mv

The Attempt at a Solution

The answer to the first question is that he should throw it away from the space station.

For the second I tried doing (V)*(82) = (7.2)(18.85), for V= 1.66 m/s but this is incorrect.

For the third, I would think that it would be 18.85-0.600 = 18.25 m/s but this is also incorrect according to the system that I'm entering this answers into.

 

[rl.bhat]

Hi dmitriylm, welcome to PF.

"For the second I tried doing (V)*(82) = (7.2)(18.85), for V= 1.66 m/s but this is incorrect".

Your substitution in the above equation is wrong.

Initially both astronaut and wrench are moving with a speed 0.600m/s.

Now apply the law of conservation of momentum.

 

[dmitriylm]

Hi dmitriylm, welcome to PF.

"For the second I tried doing (V)*(82) = (7.2)(18.85), for V= 1.66 m/s but this is incorrect".

Your substitution in the above equation is wrong.

Initially both astronaut and wrench are moving with a speed 0.600m/s.

Now apply the law of conservation of momentum.

How would I go about making up for the initial speed?

82(V-.6)=7.2(18.85+.6)?