Answer:
The runner's acceleration as she sped up to the finish line is 0.95m/s²
Explanation:
Acceleration is the change in velocity of a body with respect to time. It is expressed as;
Acceleration = change in velocity/time
Change in velocity = final velocity - initial velocity
Acceleration = final velocity - initial velocity / time
Given initial speed = 8.0m/s
Final speed = 9.9m/s
Time taken = 2.0s
Acceleration = 9.9-8.0 / 2.0
Acceleration = 1.9/2
Acceleration = 0.95m/s²
<h3><u>Answer;</u></h3>
126 joules
<h3><u>Explanation;</u></h3>
Potential energy is the energy possessed by a body while at rest.
It is calculated by the formula m×g×h; where m is the mass, h is the height and g is the gravitational acceleration, 10N/kg
Potential energy = m×g×h
= 3.0 × 4.2 × 10
<u>= 126 joules</u>
A.
<span>Geothermal energy is only practical near fault lines</span>
They rely on albedo (it’s the fraction of solar energy, which is short-wave, that’s reflected from the Earth back into space, it’s how ‘reflective’ the Earth’s surface is) to reflect a lot because if it doesn't the ice caps will melt and polar bears will lose their home
The energy required by the excitation of the line is:
ΔE = hν = hc / λ
where:
ΔE = energy difference
h = Planck constant
ν = line frequency
c = speed of light
λ = line wavelength
The energy difference must be supplied by the electron, supposing it transfers all its kinetic energy to excite the line:
Therefore,
And solving for v we get:
Plugging in numbers (after trasforing into the correct SI units of measurement):
=9.4 · 10⁵ m/s
Hence, the electron must have a speed of
9.4 · 10<span>
⁵ m/s in order to excite the <span>492nm</span> line.</span>