Wow ! This is not simple. At first, it looks like there's not enough information, because we don't know the mass of the cars. But I"m pretty sure it turns out that we don't need to know it.
At the top of the first hill, the car's potential energy is
PE = (mass) x (gravity) x (height) .
At the bottom, the car's kinetic energy is
KE = (1/2) (mass) (speed²) .
You said that the car's speed is 70 m/s at the bottom of the hill,
and you also said that 10% of the energy will be lost on the way
down. So now, here comes the big jump. Put a comment under
my answer if you don't see where I got this equation:
KE = 0.9 PE
(1/2) (mass) (70 m/s)² = (0.9) (mass) (gravity) (height)
Divide each side by (mass):
(0.5) (4900 m²/s²) = (0.9) (9.8 m/s²) (height)
(There goes the mass. As long as the whole thing is 90% efficient,
the solution will be the same for any number of cars, loaded with
any number of passengers.)
Divide each side by (0.9):
(0.5/0.9) (4900 m²/s²) = (9.8 m/s²) (height)
Divide each side by (9.8 m/s²):
Height = (5/9)(4900 m²/s²) / (9.8 m/s²)
= (5 x 4900 m²/s²) / (9 x 9.8 m/s²)
= (24,500 / 88.2) (m²/s²) / (m/s²)
= 277-7/9 meters
(about 911 feet)
The velocity of the tip of the second hand is 0.0158 m/s
Explanation:
First of all, we need to calculate the angular velocity of the second hand.
We know that the second hand completes one full circle in
T = 60 seconds
Therefore, its angular velocity is:
Now we can calculate the velocity of a point on the tip of the hand by using the formula
where
is the angular velocity
r = 15 cm = 0.15 m is the radius of the circle (the distance of the point from the centre of rotation)
Substituting,
Learn more about angular motion here:
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The number of significant digits to the answer of the following problem is four.
<h3>What are the significant digits?</h3>
The number of digits rounded to the approximate integer values are called the significant digits.
The following problem is
(2.49303 g) * (2.59 g) / (7.492 g) =
On solving we get
= 0.86184566204
The answer is approximated to 0.86185
Thus, the significant digits must be four.
Learn more about significant digits.
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I believe it is C hope i helped!
