From the choices provided, the better answer is ' T ' .
We can ignore all that business about resting on the rock and
rolling down part of the way and then resting on the moss.
Its potential energy right now doesn't depend on what happened
to it yesterday. We don't care.
All we care about is that we're walking along in the park and we
notice a 1.5kg rock lying in moss 10 meters above the ground.
Gravitational potential energy
= (mass) · (gravity) · (height)
= (1.5 kg) · (9.8 N/kg) · (10 m)
= 147 (kg · N · m / kg)
= 147 joules
Answer:
Explanation:
<u>Work
</u>
The work done by an external force F when moving an object by a distance X parallel to its direction is
The second Newton's law gives us the net force acting on an object of mass m which is being moved at an acceleration a:
Replacing the last equation into the first equation
And solving for a
There seems to be some kind of mistake in the data provided, we'll use it anyway
It's a very small value as compared to the dimensions of the rest of the problem.
The answer is 21m because the motion is in one dimension with constant acceleration.
The initial velocity is 0, because it started from rest, the acceleration <span>ax</span> is <span>4.7<span>m<span>s2</span></span></span>, and the time t is <span>3.0s</span>
Plugging in our known values, we have
<span>Δx=<span>(0)</span><span>(3.0s)</span>+<span>12</span><span>(4.7<span>m<span>s2</span></span>)</span><span><span>(3.0s)</span>2</span>=<span>21<span>m</span></span></span>
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