Answer:
50
Explanation:
The mechanical advantage of a machine is given by

where
is the output force
is the input force
For the crowbar in this problem,
is the force in input applied by the worker
is the force that the machine must apply in output to overcome the resistance of the window and to open it
Substituting into the equation, we find

Both planets are similar in shape and have a rocky surface. Not sure about the phases though
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:
Δx = 1.2 m
Explanation:
The CHANGE of spring length) (Δx) can be found using PS = ½kΔx²
Δx = √(2PS/k) = √(2(450)/650) = 1.17669... ≈ 1.2 m
The actual length of the spring is unknown as it varies with material type, construction method, extension or compression, and other variables we have no clue about.