Answer:
3.57 m/s
Explanation:
The sum of the 2 momentums Is equal the finale momentums. so if momentums Is q, v Is velocity and m Is Mass, q3=m1*v1+m2**v2=16+9=25 m*kg/s
q3=m3*v3
v3=q3/m3=25/(4+3)=3.57m/s
I believe d all of the above
#8 positive kinetic energy
In order to solve the problem, it is necessary to apply the concepts related to the conservation of momentum, especially when there is an impact or the throwing of an object.
The equation that defines the linear moment is given by

where,
m=Total mass
Mass of Object
Velocity before throwing
Final Velocity
Velocity of Object
Our values are:

Solving to find the final speed, after throwing the object we have

We have three objects. For each object a launch is made so the final mass (denominator) will begin to be subtracted successively. In addition, during each new launch the initial speed will be given for each object thrown again.
That way during each section the equations should be modified depending on the previous one, let's start:
A) 



B) 



C) 



Therefore the final velocity of astronaut is 3.63m/s
Answer:
a) and c).
Explanation:
For a complete destructive interference occur, it must be met the following condition relating the wavelength, and the difference in the paths taken by the sound emitted by the sources until arriving to the listening point:
d = |dA- dB| = (2n-1)*(λ/2)
For n= 1, d = λ/2 = 0.25 m, it doesn't meet any of the cases.
For n=2, d= 3*(λ/2) = 0.75 m
In the case a) we have dA = 2.15 m and dB = 3.00 m, so dB-dA = 0.75 m, which means that in the location stated by case a) a complete destructive interference would occur.
For n=3, d= 5*(λ/2) = 5*0.25 m = 1.25 m.
This is just the case c) because we have dA = 3.75 m and dB = 2.50 m, so dA-dB = 1.25 m, which means that in the location stated by case c) a complete destructive interference would occur also.
The remaining cases don't meet the condition stated above, so the statements found to be true are a) and c),