We must use two formulas of energy first how energy is related to wavelength:
Such that , c is the speed of light in a vacuum and h is Plank's constant.
And the second equation is how energy relates to voltage:
Such that q is the charge of the particle (in this case the electron) and V is voltage. By substituting the second equation into the first we have:
We know that:
And so:
Answer:
rolling ball down a hill
Explanation:
A rolling ball has kinetic energy
Work done on the crate is 1411.2 J
Explanation:
Work done is defined as the product of force and the distance moved by the object. The unit of work done is in joules and denoted by the symbol J.
Work done = F * d
where F represents the force and d represents the distance moved by the object.
mass = 72 kg , distance moved by the object is given by 2.0 m
Force F = mass * gravity = 72 * 9.8
= 705.6 N =706 N.
Work done = 706 * 2.0 = 1412 J.
Answer:
h = P₁ / 9800
Explanation:
This is a fluid mechanics problem, let's write the Bernoulli equation at two points, the subscript 1 for the lowest point and the subscript of 2 for the point with the highest height.
P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂
at the highest point P₂ = 0 and v₂ = 0,
P1 + ½ ρ v12 = ρ g (y₂ -y₁)
we use the continuity equation for the velocity at the lowest point
A₁ v₁ = A₂ v₂
Since the velocity at the highest point is zero, this implies from the equation that the velocity at the lowest point is also zero. In the no-flow condition
P₁ = ρ g (y₂ -y₁)
h = y₂-y₁
h = P₁ /ρ g
the density of water is ρ = 1000 kg / m³ and g = 9.8 m/s², we substitute
h = P₁ / 9800
Let's do a calculation, suppose that P₁ = 1 10⁵ Pa
h = 1 10⁵ / 9800
h = 10.2 m