A shopper pushes a grocery cart 41.9 m on level ground, against a 44.5 N frictional force. The cart has a mass of 16.3 kg. He pu
1 answer:
Answer:
Fp = 26.59[N]
Explanation:
This problem can be solved using the principle of work and energy conservation, i.e. the final kinetic energy of a body will be equal to the sum of the forces that do work on the body plus the initial kinetic energy.
We need to identify the initial data:
d = distance = 41.9[m]
Ff = friction force = 44.5 [N]
m = mass = 16.3 [kg]
v1 = 1.9 [m/s]
v2 = 12.6 [m/s]
The kinetic energy at the beginning can be calculated as follows:
And the final kinetic energy.
The work is performed by two forces, the friction force and the pushing force, it is important to clarify that these forces are opposite in direction.
The weight of the cart also performs a work in the direction of movement since the plane is tilted down, this component of the weight of the cart must be parallel to the surface of the inclined plane.
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Answer:
The components of the moving frame is (8.07c, -2, 3, 9.493)
Solution:
As per the question:
Velocity of moving frame w.r.t original frame 0.85c
Point 'a' of an event in one reference frame corresponds to the (x, y, z, t) coordinates of the plane
a = (0, - 2, 3, 5)
Now, according the the question, the coordinates of moving frame, say (X, Y, Z, t'):
New coordinates are given by:
X =
X =
X =
Now,
Y = y = - 2
Z = z = 3
Now,
Answer:
a) What is the energy of the n = 5 level?
(b) Calculate the wavelength and frequency of a photon emitted when an electron jumps down from n = 5 to n = 1 in a H atom.
,
Explanation:
The permitted energy for the atom of hydrogen according with the Bohr's model is defined as:
(1)
Or it can be expressed in Joules, since
Where the value represents the energy of the ground state¹ and n is the principal quantum number.
<em>a) What is the energy of the n = 5 level? </em>
For the case of :
So the energy of the level is
.
<em>(b) Calculate the wavelength and frequency of a photon emitted when an electron jumps down from n = 5 to n = 1 in a H atom.</em>
The wavelength can be determined by means of the Rydberg formula:
(2)
Where R is the Rydberg constant, with a value of
For this particular case and
:
Where
.
The frequency can be found by means of:
(3)
Equation (3) can be rewritten in terms of :
Where
Key terms:
¹Ground state: State of minimum energy.