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Lyrx
3 months ago
9

The equation for the change in the position of a train (measured in units of length) is given by the following expression: x = ½

at² + bt³ where a and b are constants and t is time (measured in units of time). If (mass), (length), and (time) represent units of mass, length and time respectively then b must have units of:
(A) (length)/(time)
(B) (length)/(time³)
(C) (mass)(length)
(D) (length)/(mass)
(E) (mass2)(time2)
(F) 1/(mass)(time)
(G) 1/(length)(time)
(H) (time)(mass)
(I) (mass)(time2)
(J) 1/(time³)
(K) (time)/(mass)
(L) (length)/(time²)

(mass)(length2)
Physics
2 answers:
Keith_Richards [3.2K]3 months ago
6 0
(B) (length)/(time³) Explanation: The term x = ½ at² + bt³ should meet dimensional consistency. This means that both bt³ and ½ at² must share the same units, which are length. To find the dimension of b, we rearrange the equation: [x] = [b]*[t]³ leads to length = [b]*time³, hence [b] = length/time³.
ValentinkaMS [3.4K]3 months ago
3 0
The formula representing a train's position as a function of time is given by x(t) = ½at² + bt³ where a and b are constants. We wish to identify the dimension of b. The variable x signifies length and is measured in meters, while t represents time measured in seconds. The constant b has an unknown unit, as does the constant a. With x = ½at² + bt³, we find that for dimensional correctness, units of a and b must eliminate the time units. Therefore, a should be in m/s² units. Conversely, for b to negate seconds cubed, b must be in meters/seconds³, leading to the conclusion that the unit of b is represented as meters/seconds³, which implies length/time³. Thus, the suitable answer is B.
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Sav [3153]

Answer:

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Explanation:

To calculate the kinetic energy variation, we can utilize the work-energy theorem.

W = ΔK

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If the object starts from rest, then K₀ = 0.

So, ∫ F dx cos θ = K.

As the force and displacement directions align, the angle is zero, and hence the cosine is 1.

Now we can substitute and perform integration:

α ∫ x³ dx + β ∫ dx = K.

Thus, α x⁴ / 4 + β x = K.

Next, we evaluate from the limits F = 0 to F:

α (x⁴ / 4 - 0) + β (x - 0) = K.

Consequently, K = αX⁴ / 4 + β x.

This results in K = 1.525 10⁻⁹ x⁴ + 4.1 10⁶ x.

To finalize the computation, we need to ascertain the displacement.

8 0
4 months ago
A standard baseball has a circumference of approximately 23 cm . if a baseball had the same mass per unit volume as a neutron or
Softa [3030]

Answer:

 Baseball mass:  m_b=3.992*10^{14}kg  

Explanation:

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 Thus, the radius comes out to be 3.66 cm, which equals 3.66*10^{-2} m

 The mass density of the baseball matches that of a neutron or proton.

 Proton mass = 10^{-27} kg  

 Proton diameter = 10^{-15} m

 Proton radius =  5*10^{-16} m

 Volume of the baseball is \frac{4}{3} \pi r^3

 Now by substituting all values into the mass per unit volume equation for the baseball, we get:  

         \frac{m_b}{\frac{4}{3}\pi *(3.66*10^{-2})^3} =\frac{10^{-27}}{\frac{4}{3}\pi *(5*10^{-16})^3}

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5 0
3 months ago
Read 2 more answers
A 5-kg concrete block is lowered with a downward acceleration of 2.8 m/s2 by means of a rope. The force of the block on the Eart
Maru [3345]

The moment the body impacts the ground, two types of Forces are produced: the gravitational pull and the Normal Force. This aligns with Newton's third law, indicating that every action has an equal and opposite reaction. If the downward force of gravity is directed toward the earth, the reactionary force from the block acts upwards, equivalent to its weight:

F = mg

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Consequently, the answer is E.

5 0
3 months ago
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