Given that,
Height =1.5 m
Angle = 45°
We need to find the greater speed of the ball
Using conservation of energy


Here, initial velocity and final potential energy is zero.

Put the value into the formula




Hence, the greater speed of the ball is 5.42 m/s.
Planet A;
m = the mass
Let r = the radius
Planet B:
Let M = the mass
The radius is 2r (twice the radius of planet A)
The surface gravitational acceleration of planets A and B (they have the same surface gravity) are

Answer: The mass of planet B is 4m.
Answer:
By the information given, I am not sure how the event has played out. However, using common knowledge, I can give a scenario of how it may play out.
When removing the first block (the foundation), gravity will pull the other blocks down, as the strength of gravity exceeds that of the strength of air holding it up. This means that all the blocks on top would fall.
By definition of Newton's 1st - 3rd laws, the blocks would not move unless a force is given to it (i.e., removing the bottom block, which causes gravity). Gravity would pull the other blocks downwards. This would lead to the falling of the stack of blocks.
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