We can solve the problem by using the law of conservation of energy.
Using the ground as reference point, the mechanical energy of the brick when it is at 5 m from the ground is just potential energy (because the brick is initially at rest, so it doesn't have kinetic energy):

when the brick is at h'=3 m from the ground, its mechanical energy is now sum of kinetic energy and potential energy:

where v is the velocity of the brick. Since E is conserved, it must be equal to the initial energy (98.1 J), so we can solve this equation to find v:
Answer:
(a) v = 15m/a
(b) No they won't feast because the rock can only rise to a height of 11.5m which is less than 15m.
Explanation:
Please see the attachment below for film solution.
Answer:
Show attached picture
Explanation:
Let's call V the voltage provided by the battery in the circuit. M is the multimeter (let's call
its internal resistance) and R indicates the resistance of the light bulb.
We know that the meter's internal resistance is 1000 times higher than the bulb's resistance:
(1)
Both the meter and the bulb are connected in parallel to the battery, so they both have same potential difference at their terminals:

Using Ohm's law,
, we can rewrite the previous equation as:

where
is the current in the meter
is the current in the bulb
Using (1), this equation becomes

so, the current in the meter is 1000 times less than through the bulb.
The answer for this problem is clarified through this, the
system is absorbing (+). And now see that it uses that the SURROUNDINGS are
doing 84 KJ of work. Any time a system is overshadowing work done on it by the
surroundings the sign will be +. So it's just 12.4 KJ + 4.2 = 16.6 KJ.