Answer:
The kinetic energy when it returns to its original height is 100 J
Explanation:
The ball is thrown up with a Kinetic Energy K. E. = 0.5×m×v² = 100 J
Therefore the final height is given by
u² = v² -2·g·s
Where:
u = final velocity = 0
v = initial velocity
s = final height
Therefore v² = 2·g·s = 19.62·s
P.E = Potential Energy = m·g·s
Since v² = 2·g·s
Substituting the value of v² in the kinetic energy formula, we obtain
K. E. = 0.5×m×2·g·s = m·g·s = P.E. = 100 J
When the ball returns to the original height, we have
v² = u² + 2·g·s
Since u = 0 = initial velocity in this case we have
v² = 2·g·s and the Kinetic energy = 0.5·m·v²
Since m and s are the same then 0.5·m·v² = 100 J.
ANSWER: C. The author is opposed to the light-rail project.
EXPLANATION: The author understands the mentality and the sentiments of Americans. He knows the fact very well that people would never compromise their comfort, joy and freedom to become a good citizen. The author thinks they can be rather advised to buy high quality cars with good fuel efficiency than using the light rail system. So, to avoid taxpayers' millions of dollars, he wants the citizens to vote against it.
The height of the projectile is given by:
h = ut - 0.5at²
The height will be 0 twice, once at t = 0 and the second time at the time when the journey has been completed, or t = hang time.
0 = 7.3t - 0.5(9.81)t²
t = 1.49 seconds
Answer:
The Hubble telescope,which is taking detailed pictures of the universe.
Explanation:
