Answer:
17.82J
Explanation:
Kinetic energy = 1/2 mv^2
Given
Mass M = 0.45kg
Velocity v = 8.9m/s
Therefore,
K.E. = 1/2 x 0.45 x (8.9)^2
= 1/2 x 0.45 x (8.9 x 8.9)
= 1/2 x 0.45 x 79.21
Multiply through
= 35.6445/2
= 17.82J
The kinetic energy of the ball is 17.82J
In order to find the final velocity of the skier and the trash can lid, we may apply the principle of conservation of momentum, which states that the total momentum of a system remains constant. Mathematically, in this case:
m₁v₁ + m₂v₂ = m₃v₃
Where m₃ and v₃ are the combined mass and velocity.
75*3 + 10*2 = (75 + 10)*v₃
v₃ = 2.88 m/s
The final velocity is 2.88 m/s
I would tell him, in the kindest, most gentle way I could manage,
to fahgeddaboudit.
The total amount of energy doesn't change. Energy is never created,
and it never disappears. If you have some energy, then it had to come
from somewhere, and if you used some energy, then it had to go
somewhere.
You can never get more energy out of the electromotor than you put into it,
and in the real world, you can't even get THAT much out, because some
of it is always used on the way through.
Pour yourself a cold glass of soda, then look up "Perpetual Motion" or
"Free Energy" on the internet, relax, and enjoy the show. They are all
fakes. They may not all be intentionally meant to fool you, but they are
all impossible.
Time = (distance) / (speed)
Time = (150 x 10⁹ m) / (3 x 10⁸ m/s) =
50 x 10¹ sec =
<em>500 sec</em> = 8 min 20 sec
