Answer:
From the second law of motion:
F = ma
we are given that the force applied on the block is 20N and the block accelerates at an acceleration of 4 m/s/s
So, F= 20N and a = 4 m/s/s
Replacing the variables in the equation:
20 = 4* m
m = 20 / 4
m = 5 kg
The best and most correct answer among the choices provided by the question is decreases <span>.
</span>The potential energy of the object <span>decreases.</span>
Hope my answer would be a great help for you.
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Answer:
You could move something across the Earth with a little push. It would make fuel really efficient on those pathways. You could make a floor that is impossible to walk on. Everybody would just fall without traction.
Explanation:
<span>The runner is moving by uniformly accelerated motion, starting from rest (so, his initial velocity is zero). The law of motion of the runner is
</span>

<span>
where x(t) is the distance covered after time t, and a is the acceleration of the runner. By re-arranging the formula, we get
</span>

<span>
We know the runner has covered a distance of S=12m in t=4.0 s, and if we plug these numbers into the equation, we find the acceleration of the runner:
</span>

<span>
</span>