Hi there!
Initially, we have gravitational potential energy and kinetic energy. If we set the zero-line at H2 (12.0m), then the ball at the second building only has kinetic energy.
We also know there was work done on the ball by air resistance that decreased the ball's total energy.
Let's do a summation using the equations:
Our initial energy consists of both kinetic and potential energy (relative to the final height of the ball)
Our final energy, since we set the zero-line to be at H2, is just kinetic energy.
And:
The work done by air resistance is equal to the difference between the initial energy and the final energy of the soccer ball.
Therefore:
Solving for the work done by air resistance:
Thermal energy is added to four identical<span> 1.0 kg </span>samples of water<span> at room temperature. Which of the following </span>increases in each sample<span>? average charge of an electron; average density of </span>a<span> nucleus; average mass of </span>a<span> proton; average speed of </span>a<span> molecule. Your answer: -. Answer: D - average speed of </span>a<span>molecule.</span>
Answer:
filament bulb, filament lamp
Explanation:
1. C. Gravitational attraction exists between the two objects.
Explanation:
Gravitational attraction is always exerted between two objects which have mass, and its magnitude is given by:
where G is the gravitational constant, m1 and m2 the masses of the two objects, and r the separation between them. Since the two objects have for sure non-zero masses m1 and m2, even if they are 20 miles apart, the value of the gravitational attraction F is non-zero, so the correct answer is C.
2. D. Two atoms come together to form a molecule.
Explanation:
this outcome is actually caused by the electrostatic forces between the two atoms, not by gravitational force. In fact, gravitational force becomes relevant only when the masses of the two objects involved are large enough: this is the case for planets, stars, galaxies, and objects in the universe. However, two atoms have very small masses, so the gravitational force between them is really negligible. On this smaller scales, the electrostatic force is much stronger than the gravitational force, so the electrostatic force is the real responsible for the formation of bonds between atoms.
Answer:
Explanation:
mass of the ball = 146 g = 146 / 1000 = 0.146 kg
initial speed of the ball = 40.6 m/s
final speed of the ball = - 45.1 m/s
time of impact = 1.05 ms = 1.05 / 1000 = 0.00105 s
impulse, Ft = change in momentum = mv - mu = m (v-u)
F = m (v - u) / t = 0.146 kg ( -45.1 -40.6) / 0.00105 s = -11916.4 N
