Answer:
the first one.
Explanation: I don't exactly but, I know the other three sounds more like repetition! Hope this helps
Answer:
A) some of the rocks energy is transformed to thermal energy
Explanation:
If we neglect air resistance during the fall of the rock, than the mechanical energy of the rock (which is sum of its potential energy and its kinetic energy) would be constant during the entire motion, so the total energy of the rock at the top would be the same as the sum of its potential energy and kinetic energy at the bottom.
However, this not occurs, due to the presence of air resistance. In fact, air resistance acts against the fall of the rock, and because of the friction between the molecules of air and the surface of the rock, the rock loses part of its energy. This energy is converted into thermal energy of the molecules of the air.
Answer:
B
Explanation:
kinetic energy (KE) is the energy possessed by moving bodies. It can be expressed as:
KE = m
Where: m is the mass of the object, and v its speed.
For example, a stone of mass 2kg was thrown and moves with a speed of 3 m/s. Determine the kinetic energy of the stone.
Thus,
KE = x 2 x
= 9
KE = 9.0 Joules
Assume that the speed of the stone was 4 m/s, then its KE would be:
KE = x 2 x
= 16
KE = 16.0 Joules
Therefore, it can be observed that as speed increases, the kinetic energy increases. Thus option B is appropriate.
Answer:
D is the answer I think (0 w 0 )
Explanation:
The work done against gravity is 100 J
Explanation:
The work done against gravity in order to lift an object is equal to the change in gravitational potential energy of the object:
where
m is the mass of the object
g is the acceleration of gravity
is the change in height of the object
For the object in this problem, we have:
m = 5 kg
Substituting into the equation,
Learn more about work:
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