Is metal a matter or molecules
2 answers:
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Answer:
(a). Their speed during that run is 10 m/s.
(b). Their velocity is 6.86 m/s
(c). The final position is at 8.91 m.
Explanation:
Given that,
A football player starts at the 40-yard line, and runs to the 25-yard line in 2 seconds.
Suppose, the distance between 40 yard line and 25 yard line is 20 yard.
(a). We need to calculate their speed during that run
Using formula of speed
Where. d = distance
t = time
Put the value into the formula
during that run
(b). We need to calculate their velocity
Using formula of speed
Put the value into the formula
Negative sign shows the direction of motion.
(c). If they kept running at that velocity for another 1.3 seconds,
We need to calculate the final position
Using formula of position
Put the value into the formula
Hence, (a). Their speed during that run is 10 m/s.
(b). Their velocity is 6.86 m/s
(c). The final position is at 8.91 m.
Answer:
A) = 1.44 kg m², B) moment of inertia must increase
Explanation:
The moment of inertia is defined by
I = ∫ r² dm
For figures with symmetry it is tabulated, in the case of a cylinder the moment of inertia with respect to a vertical axis is
I = ½ m R²
A very useful theorem is the parallel axis theorem that states that the moment of inertia with respect to another axis parallel to the center of mass is
I = + m D²
Let's apply these equations to our case
The moment of inertia is a scalar quantity, so we can add the moment of inertia of the body and both arms
=
+ 2
= ½ M R²
The total mass is 64 kg, 1/8 corresponds to the arms and the rest to the body
M = 7/8 m total
M = 7/8 64
M = 56 kg
The mass of the arms is
m’= 1/8 m total
m’= 1/8 64
m’= 8 kg
As it has two arms the mass of each arm is half
m = ½ m ’
m = 4 kg
The arms are very thin, we will approximate them as a particle
= M D²
Let's write the equation
= ½ M R² + 2 (m D²)
Let's calculate
= ½ 56 0.20² + 2 4 0.20²
= 1.12 + 0.32
= 1.44 kg m²
b) if you separate the arms from the body, the distance D increases quadratically, so the moment of inertia must increase