Answer:
(a) α = -0.16 rad/s²
(b) t = 33.2 s
Explanation:
(a)
Applying 3rd equation of motion on the circular motion of the tire:
2αθ = ωf² - ωi²
where,
α = angular acceleration = ?
ωf = final angular velocity = 0 rad/s (tire finally stops)
ωi = initial angular velocity = 5.45 rad/s
θ = Angular Displacement = (14.4 rev)(2π rad/1 rev) = 28.8π rad
Therefore,
2(α)(28.8π rad) = (0 rad/s)² - (5.45 rad/s)²
α = -(29.7 rad²/s²)/(57.6π rad)
<u>α = -0.16 rad/s²</u>
<u>Negative sign shows deceleration</u>
<u></u>
(b)
Now, we apply 1st equation of motion:
ωf = ωi + αt
0 rad/s = 5.45 rad/s + (-0.16 rad/s²)t
t = (5.45 rad/s)/(0.16 rad/s²)
<u>t = 33.2 s</u>
The answer for this question is D
To solve this problem we will apply the concept related to the heat transferred to a body to reach a certain temperature. This concept is shaped by the energy ratio of a body which is the product of the mass, its specific heat and the change in temperature. For the specific case, it will be the sum of the heat transferred to the Water, the Aluminum and the loss due to latency due to vaporization in the water. That is to say,

Here,
= Mass of Aluminum
= Specific Heat of Aluminum
= Specific Heat of Water
Mass of water
Latent of Vaporization
Replacing,

Converting,


Therefore is required 440.409kCal
Answer: Impulse = 4 kgm/s
Explanation:
From the question, you're given the following parameters:
Momentum P1 = 12 kgm/s
Momentum P2 = 16 kgm/s
Time t = 0.2 s
According to second law of motion,
Force F = change in momentum ÷ time
That is
F = (P2 - P1)/t
Cross multiply
Ft = P2 - P1
Where Ft = impulse
Substitute P1 and P2 into the formula
Impulse = 16 - 12 = 4 kgm/s
The magnitude of the impulse is therefore 4 kgm/s.