Answer:
3.76 m/s
Explanation:
Instantaneous velocity: This can be defined as the velocity of an object in a non uniform motion. The S.I unit is m/s.
v' = dx(t)/dt..................... Equation 1
Where v' = instantaneous velocity, x = distance, t = time.
Given the expression,
x(t) = 28.0 m + (12.4 m/s)t - (0.0450 m/s³)t³
x(t) = 28 + 12.4t - 0.0450t³
Differentiating x(t) with respect to t.
dx(t)/dt = 12.4 - 0.135t²
dx(t)/dt = 12.4 - 0.135t²
When t = 8.00 s.
dx(t)/dt = 12.4 - 0.135(8)²
dx(t)/dt = 12.4 - 8.64
dx(t)/dt = 3.76 m/s.
Therefore,
v' = 3.76 m/s.
Hence, the instantaneous velocity = 3.76 m/s
It's 3.6 meters per second less than my speed was
at 4:19 PM last Tuesday.
Does that tell you anything ?
Why not ?
Answer:
The resistance is 
Explanation:
Given that,
Diameter of tube = 8.5 mm
Length = 8 cm
Resistivity = 2.5 m
We need to calculate the resistance
The resistance is equal to the product of the resistivity and length divided by the area of cross section .
In mathematical form,
Where, 
=resistivity
l = length
A = area of cross section
Put the value into the formula
Hence, The resistance is
4200 N is the tension in the cable that pulls the elevator upwards.
The correct option is A.
<h3>What does tension ?</h3>
Tension is the force that is sent through a rope, thread, or wire whenever two opposing forces pull on it. Along the whole length of the wire, the tensile stress pulls equally on all objects at the ends. Every physical object that comes into contact with that other one exerts force on it.
<h3>Briefing:</h3>
We employ the following formula to determine the cable's tension.
Formula:
T = mg+ma............ Equation 1
Where:
T is the cable's tension.
M = Mass of the elevator and the Joey
Accelerating with a
g = Gravitational acceleration
Considering the query,
Given:
m = (300+60) = 360 kg
a = 2 m/s²
g = 9.8 m/s²
Substitute these values into equation 2
T = (360×9.8)+(360×2)
T = 3528+720
T = 4248 N
T ≈ 4200 to the nearest hundred.
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