The energy transfer diagram represents the energy of a person diving into a pool.
2 answers:
The correct answer is:
<span>A) 1000 J
In fact, energy cannot be destroyed nor created: this means that the total energy of the person must remain constant.
The initial energy of the person is U=8000 J, in form of gravitational potential energy. When he jumps and dives into the pool, this energy is converted into kinetic energy (K, 7000 J) and partially into thermal energy, Et. The final energy of the person, sum of kinetic energy and thermal energy, must be equal to the initial energy:
</span>
<span>from which we can find the thermal energy:
</span>
<span>
</span>
<span>A) 1000 J
In fact, energy cannot be destroyed nor created: this means that the total energy of the person must remain constant.
The initial energy of the person is U=8000 J, in form of gravitational potential energy. When he jumps and dives into the pool, this energy is converted into kinetic energy (K, 7000 J) and partially into thermal energy, Et. The final energy of the person, sum of kinetic energy and thermal energy, must be equal to the initial energy:
</span>
<span>from which we can find the thermal energy:
</span>
</span>
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Answer:
The range of powers is
Explanation:
From the question we are told that
The far point of the left eye is
The near point of the left eye is
The near point with the glasses on is
From these parameter we can see that with the glass on that for near point the
Object distance would be
Image distance would be
To obtain the focal length we would apply the lens formula which is mathematically represented as
substituting values
converting to meters
Generally the power of the lens is mathematically represented as
Substituting values
From these parameter we can see that with the glass on that for far point the
Object distance would be
Image distance would be
To obtain the focal length of the lens we would apply the lens formula which is mathematically represented as
substituting values
converting to meters
Generally the power of the lens is mathematically represented as
Substituting values
This implies that the range of powers of the lens in his glass is
Answer:
E. Zero Maximum
Explanation:
At the point of maximum displacement, the speed is zero while the restoring force is maximum. In fact:
- The restoring force is given by , where k is the spring constant and x is the displacement - at the point of maximum displacement, x is maximum, so F is maximum as well
- the total energy of the system is sum of kinetic energy and elastic potential energy:
where m is the mass of the system and v is the speed. Since E (the total energy) is constant due to the law of conservation of energy, we have that when K increases, U decreases, and viceversa. As a result, when x increases, v decreases, and viceversa. At the point of maximum displacement, x is maximum, so v will have its minimum value (which is zero, since the system is changing direction of motion).