a person can throw a 300 gram ball at 25 m/s the maximum height the person can throw the ball on Earth?
1 answer:
Answer:
Elevation =31.85[m]
Explanation:
We can solve this problem by using the principle of energy conservation. This consists of transforming kinetic energy into potential energy or vice versa. For this specific case is the transformation of kinetic energy to potential energy.
We need to first identify all the input data, and establish a condition or a point where the potential energy is zero.
The point where the ball is thrown shall be taken as a reference point of potential energy.
m = mass of the ball = 300 [gr] = 0.3 [kg]
v = initial velocity = 25 [m/s]
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Work is done when a force is in the same direction as the object moves.
Explanation:
The work done by a force in moving an object is given by the equation
where
F is the magnitude of the force
d is the displacement of the object
is the angle between the directions of F and d
From the equation, we notice the following:
- Work is done by a force when the force is in the same direction as the object moves. In fact, in this case,
, and so
, which means that the work done simply becomes
- When the force is perpendicular to the motion of the object,
and
, which means that no work done
- Technically, work is also done when the force is not parallel to the motion of the object: in this case, the factor
means that only the component of the force parallel to the direction of motion contributes to do work on the object.
Therefore, the correct answer is
Work is done when a force is in the same direction as the object moves.
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Answer:
a)n =7 , b) n = 5
Explanation:
The energy levels of the hydrogen atom is described by the Bohr model
= - 13.606 1/n²
This equation energy is given in elector volts and n is an integer
A transition occurs when the electro sees from a superior to a lower state
E₀ - = -13.606 (1/
² - 1/n₀²)
Let's apply this expression
n₀ = 2
Let's look for the energy of the different levels and subtract it
n₀ (eV)
1 -13,606
2 -3.4015
3 - 1.5118
4 -0.850375
5 -0.54424
6 -0.3779
7 -0.2777
The wavelength of the transition is 397 nm = 397 10⁻⁹ m
The speed of light is related to wavelength and frequency
c = λ f
The Planck equation gives the energy of a transition
E = h f
E = h c /λ
Let's calculate
E = 6.63 10⁻³⁴ 3 10⁸/397 10⁻⁹
E = 5.01 10⁻¹⁹ J
Let's reduce to eV
E = 5.01 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹ J)
E = 3.1313 eV
Let's examine the possible transitions from the initial level ni = 2
ΔE = -
= -3.1313
En = 3.13 -3.4015
= 0.2702 eV
When examining the table we see that the level that this energy has is the level of n = 7
Part B the transition is in the infrared
The frequency is 74 10¹² Hz
We use the Planck equation
E = h f
E = 6.63 10⁻³⁴ 74 10¹²
E = 4.9062 10⁻²⁰ J
E = 4.9062 10⁻²⁰ / 1.6 10⁻¹⁹
E = 0.3066 eV
We look for the level with the energy difference
ΔE = E₄- = 0.3066
= 0.3066 - 0.85037
= -0.54376 eV
When examining the table this energy has the level n = 5, therefore from this level the transition occurs
1. Amperes, is the SI unit (also a fundamental unit) responsible for current.
2. Δq over Δt technically
Rearrange for Δq
I x Δt = Δq
1.5mA x 5 = Δq
Δq = 0.0075
Divide this by the fundamental charge "e"
Electrons: 0.0075 / 1.60 x 10^-19
Electrons: 4.6875 x 10^16 or 4.7 x 10^16
3. So we know that the end resistances will be equal so:
ρ = RA/L
ρL = RA
ρL/A = R
Now we can set up two equations one for the resistance of the aluminum bar and one for the copper: Where 1 represents aluminum and 2 represents copper
We are looking for L2 so we can isolate using algebra to get:
If you fill in those values you get 0.0205
or 2.05 cm