For the first challenge, Lex demands that Superman use the weight of a small stone to lift a boulder. Understanding the principl
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Given :
The focal length of a concave mirror is 18 cm.
To Find :
The radius of curvature of the concave mirror.
Solution :
We know,
Therefore, the radius of curvature of concave mirror is 36 cm.
Hence, this is the required solution.
1) The most potential energy is at position A
2) The most kinetic energy is at position C
Explanation:
1)
The gravitational potential energy is the energy possessed by an object due to its position in a gravitational field, and it is given by the equation
where
m is the mass of the object
g is the acceleration of gravity
h is the height of the object relative to the ground
From the equation, we see that the potential energy is directly proportional to the heigth of the object: therefore, the roller coaster in this problem will have the most potential energy at its highest postion, so at position A.
2)
The total mechanical energy of the roller coaster at any point along the track is given by
where
PE is the potential energy
KE is the kinetic energy
Assuming there is no friction, the mechanical energy E is constant. This means that when PE increases, KE decreases, and when PE increases, KE decreases.
Therefore, the cart will have maximum kinetic energy when the potential energy is at minimum: and since the potential energy is directly proportional to the height of the track, this will occur at the lowest position, so at position C.
Learn more about kinetic and potential energy:
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Answer:
14.3kg
Explanation:
Given parameters:
Quantity of heat = 149000J
Change in temperature = 5.23°C
specific heat of the ice = 2000J/kg°C
Unknown:
Mass of the ice in the bag = ?
Solution:
The heat capacity of a substance is given as:
H = m c Ф
H is the heat capacity
m is the mass
c is the specific heat
Ф is the temperature change;
since m is the unknown, we make it the subject of the expression;
m = H/ mФ
m = = 14.3kg