Answer:
The mass of the object, its acceleration due to gravity and the distance between the top of the hill and the ground level.
Explanation:
gravitational potential energy is the energy possessed by a body under influence of gravitational force by virtue of its position.
In order to determine the gravitational potential energy of the brick, we must know the mass (m) of the brick, its acceleration due to gravity (g) since it is acting under the influence of gravitational force and the distance between the top of the hill and the ground level. (The height).
Potential energy of a body is calculated as mass × acceleration due to gravity × height.
Answer:
a) 
, b) 
Explanation:
The magnitude of torque is a form of moment, that is, a product of force and lever arm (distance), and force is the product of mass and acceleration for rotating systems with constant mass. That is:
Where 
is the angular acceleration, which is constant as torque is constant. Angular deceleration experimented by the unpowered flywheel is:
Now, angular velocities of the unpowered flywheel at 50 seconds and 100 seconds are, respectively:
a) t = 50 s.
b) t = 100 s.
Given that friction is of reactive nature. Frictional torque works on the unpowered flywheel until angular velocity is reduced to zero, whose instant is:
Since 
, then the angular velocity is equal to zero. Therefore:
Answer:
R_cm = 4.66 10⁶ m
Explanation:
The important concept of mass center defined by
R_cm = 1 / M ∑ x_i m_i
where M is the total mass, x_i and m_i are the position and masses of each body
Let's apply this expression to our case.
Let's set a reference frame where the axis points from the center of the Earth to the Moon,
R_cm = 1 / M (m_earth 0 + m_moon d)
the total mass is
M = m_earth + m_moon
the distance from the Earth is zero because all mass can be considered to be at its gravimetric center
let's calculate
M = 5.98 10²⁴ + 7.35 10²²
M = 6.0535 10₂⁴24 kg
we substitute
R_cm = 1 / 6.0535 10²⁴ (0 + 7.35 10²² 3.84 )
R_cm = 4.66 10⁶ m
Answer:
1. 0.574 kJ/kg
2. 315.7 MW
Explanation:
1. The mechanical energy per unit mass of the river is given by:
Where:
Ek is the kinetic energy
Ep is the potential energy
v is the speed of the river = 3 m/s
g is the gravity = 9.81 m/s²
h is the height = 58 m
Hence, the total mechanical energy of the river is 0.574 kJ/kg.
2. The power generation potential on the river is:
Therefore, the power generation potential of the entire river is 315.7 MW.
I hope it helps you!
