Answer:
α = -0.01625 rad / s²
Explanation:
This is an exercise in angular kinematics, we can use the relation
w = w₀ + 2 α θ
linear and angular variables are related
v = w r
w = v / r
Let's reduce the magnitudes to the SI system
v₀ = 91 km / h (1000m / 1km) (1h / 3600s) = 25.278 m / s
v = 48 km / h = 13,333 m / s
θ = 75 rev (2π rad / 1 rev) = 471.24 rad
Let's find the angular velocities
w₀ = v₀ / r
w₀ = 25.278 / 0.78
w₀ = 32,408 rad / s
w = v / r
w = 13.333 / 0.78
w = 17.09 rad / s
we calculate the angular acceleration
α = (w- w₀) / 2θ
α = (17.09 - 32.408) / (2 471.24)
α = -0.01625 rad / s²
the negative sign indicates that the wheel is stopping
Answer:
A force is a push or a pull. It causes an object at rest to move. It can cause an object that is moving to change speed, or the distance covered over time. It can also change which way the object is moving its direction. Lastly, it can also cause an object to stop moving completely. A force has both magnitude and direction. An object with balance forces or a net force of zero will not change position.
Explanation:
Answer:
= 128.3 J / kg ° C
Explanation:
In this exercise we will use that the expression for heat is
Q = m ΔT
As they indicate that there are no losses with the medium, the heat transferred by the tungsten is equal to the heat absorbed by the water plus the calorimeter
Q assigned = QAbsorbed
Q hot = Q cold + Q calorimeter
The mass of tungsten (m₁ = 69.12 10⁻³ kg) with an initial temperature (T₁ = 98.93°C),
The mass of water (m₂ = 85.45 10⁻³ kg) at a temperature (T₂ = 23.82°C),
a calorimeter constant (C = 1.56 J/ °C)
m₁ (T₁ - ) = (m₂ + C) ( - T₂)
= (m₂ ce2 + C) (-T₀) / (m₁ (T₁-)
= (85.45 10-3 4186 + 1.56) (25.63 - 23.82) / (69.12 10-3 (98.93 - 25.63))
= (357.69 + 1.56) 1.81 / (69.12 10-3 73.3)
= 650.24 / 5.0665
= 128.3 J / kg ° C