Answer:
Its mechanical energy is the same.
Explanation:
If forces are only conservative, the mechanical energy will be the same.
It can be different if energy get transformed in another kind of energy like elastic energy for example, although the amount of energy is always the same.
If we just have mechanical energy not geting transformed we have:
Em=K+U
Em: Mechanical energy
K: Kinetic energý
U: Potential energy
Then if Kinetic energy decreases 10J, Potential energy will grow up 10J to keep the same amount of mechanical energy.
Power is needed for (1) acceleration and (2) lifting the loaded chairs. These two parts can be calculated separately and then added together.
(1) Power for acceleration:
The final speed of the lift is
V=(10 km/h)(1 h×1000 m60 sec×1 km)=2.887 m/s.
Then the power needed is
Pa=12m(V2−V20)/Δt=12(50×250 kg)(2.778 m/s)2=9.6 kW.
(2) Power for lift
Assume that the acceleration is constant (i.e. power supply is constant), its value will be
a=ΔVΔt=2.778 m/s5 s=0.556 m/s2.
Then the vertical lift during acceleration will be
(12at2)×(2001000)=1.36 m.
Hence, the power needed to increase the potential energy of the lift is
Pg=mgΔhΔt=(50×250 kg) (9.89 m/s2)(1.36 m)/(5 s)=3.41 kW.
Then the total Power required is
Ptotal=Pa+Pg=9.6+34.1=43.7 kW.
Learn more about potential energy at
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Answer:
The answer is "Walk three days a week, gradually adding distance and hills."
Explanation:
The FITT Principle <u>guides a person in becoming a fitter version of himself by following a particular frequency, intensity, time and type of exercise in order to achieve his goals.</u>
<u>Frequency</u>- this refers to how often a person should do an exercise. For example, 5 times a week of intense core workout.
<u>Intensity</u>- this refers to the person's vigour or strength in doing the workout. This depends whether the person is doing a high-intensity or a low-intensity exercise.
<u>Time</u>- this refers to the length of a person's exercise. This will largely depend on every individual's fitness level.
<u>Type of Exercise</u>- this refers to the exercise that a person should incorporate in his training<u> in order to avoid injuries of using the same muscles over and over again.</u>
Among the choices above, it is only the second choice (Walk three days a week, gradually adding distance and hills) that follows the FITT principle. Walking shouldn't be kept at the same pace and distance for many weeks, since it results to<em> boredom and overuse injuries. </em>This will also lead to a plateau when it comes to people who are trying to lose weight because the body has already well-adjusted to the exercise and cannot be challenged anymore.
<em>Gradually increasing the distance and hills will allow the person to be more challenged </em>and<em> </em>will also increase his desire to workout (because he is seeing results).
We're millions of miles away from mars
Answer:
E = 1.04*10⁻¹ N/C
Explanation:
Assuming no other forces acting on the proton than the electric field, as this is uniform, we can calculate the acceleration of the proton, with the following kinematic equation:
As the proton is coming at rest after travelling 0.200 m to the right, vf = 0, and x = 0.200 m.
Replacing this values in the equation above, we can solve for a, as follows:
According to Newton´s 2nd Law, and applying the definition of an electric field, we can say the following:
F = mp*a = q*E
For a proton, we have the following values:
mp = 1.67*10⁻²⁷ kg
q = e = 1.6*10⁻¹⁹ C
So, we can solve for E (in magnitude) , as follows:
⇒ E = 1.04*10⁻¹ N/C
