A student lefts a bouncy ball to 1.2m, then releases the ball. The ball bounces back up to 0.86m. Construct an explanation as to
2 answers:
Answer:
the decrease in energy is due to a transformational in internal energy of the body in the rebound.
Explanation:
For this exercise we can calculate the initial and final mechanical energy
Em₀ = U = m g y₁
= U = m g y₂
we look for the variation of the energy
ΔEm = Em_{f} - Em₀
ΔEm = m g (y_{f} -y₀)
ΔEm = m g (0.86 -1.2)
ΔEm = -3.332 m
We can see that there is a decrease in mechanical energy, this is transformed into internal energy of the ball during the impact with the ground, this energy can be formed by several factors such as a part of the friction with the surface, an increase in body temperature or a deformation of the body; there may be a contribution from several of these factors.
In conclusion the decrease in energy is due to a transformational in internal energy of the body in the rebound.
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Answer:
(A) 12.222 ohm (B) 990 W
Explanation:
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Answer:
g' = g/4
Explanation:
- The value of the free-fall acceleration at the surface of the earth, can be obtained applying Newton's 2nd law, assuming that the only force acting on an object at the surface of the earth, is the one produced by the mass of the Earth, i.e. gravity.
- This force can be expressed according the Newton's Universal Law of Gravitation , as follows:
- From Newton's 2nd Law, we have:
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- Simplifying the mass m, we can write the acceleration a in (2) as the acceleration due to gravity, g, as follows:
- Since G is an universal constant, and the mass mE remains constant, if we double the radius of the Earth, the new value for the acceleration due to gravity (let's call it g'), is as follows: