When the ultrasound beam strikes the surface at or nearly at right angles, the fraction of sound energy that is reflected (R) at
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Answer:
Explanation:
The capacitance of the parallel-plate capacitor is given by
where
ϵ0 = 8.85x10-12 C2/N.m2 is the vacuum permittivity
k = 3.00 is the dielectric constant
is the area of the plates
d = 9.00 mm = 0.009 m is the separation between the plates
Substituting,
Now we can calculate the energy of the capacitor, given by:
where
C is the capacitance
V = 15.0 V is the potential difference
Substituting,
Answer:
1.35m
Explanation:
At the highest point of the jump, the vertical speed of the skier should be 0. So the 13m/s speed is horizontal, this speed stays the same from the jumping point to the highest point. The 14m/s speed at jumping point is the combination of both vertical and horizontal speeds.
The vertical speed at the jumping point can be computed:
When the skier jumps to the its potential energy is converted to kinetic energy:
where m is the skier mass and h is the vertical distance traveled, is the vertical velocity at jumping point, and h is the highest point.
Let g = 10m/s2
We can divide both sides of the equation by m: