Answer:
a) about 20.4 meters high
b) about 4.08 seconds
Explanation:
Part a)
To find the maximum height the ball reaches under the action of gravity (g = 9.8 m/s^2) use the equation that connects change in velocity over time with acceleration.
In our case, the initial velocity of the ball as it leaves the hands of the person is Vi = 20 m/s, while thw final velocity of the ball as it reaches its maximum height is zero (0) m/s. Therefore we can solve for the time it takes the ball to reach the top:
Now we use this time in the expression for the distance covered (final position Xf minus initial position Xi) under acceleration:
Part b) Now we use the expression for distance covered under acceleration to find the time it takes for the ball to leave the person's hand and come back to it (notice that Xf-Xi in this case will be zero - same final and initial position)
To solve for "t" in this quadratic equation, we can factor it out as shown:
Therefore there are two possible solutions when each of the two factors equals zero:
1) t= 0 (which is not representative of our case) , and
2) the expression in parenthesis is zero:
Using fossil fuels to generate electricity doesn't take spinning turbines. Using the force of the wind (wind energy) to generate does contain spinning, though not of generators.
Actually the
Kinetic Energy, which is also known as the energy of motion is directly
proportional to temperature. So the higher the temperature is, the faster the gas
particles move so they have possess more kinetic energy.
This temperature is in
absolute units so we convert to Kelvin:
200 C = 473.15 K
100 C = 373.15 K
So the amount increase
is:
473.15 / 373.15 =
1.268
<span>It will increase by a
factor of 1.268 or 126.8%</span>
Answer:
These energy exchanges are not changes in kinetic energy. They are changes in bonding energy between the molecules. If heat is coming into a substance during a phase change, then this energy is used to break the bonds between the molecules of the substance. The example we will use here is ice melting into water.
Explanation:
Medium is the material in which a mechanical wave travels.