Answer:
Depends
Explanation:
This depends on the amount of work the energy requires
Answer:
115 m/s, 414 km/hr
Explanation:
There are two forces acting on a skydiver: gravity and air resistance (drag). At terminal velocity, the two forces are equal and opposite.
∑F = ma
D − mg = 0
D = mg
Drag force is defined as:
D = ½ ρ v² C A
where ρ is the fluid density,
v is the velocity,
C is the drag coefficient,
and A is the cross sectional surface area.
Substituting and solving for v:
½ ρ v² C A = mg
v² = 2mg / (ρCA)
v = √(2mg / (ρCA))
We're given values for m and A, and we know the value of g. We need to look up ρ and C.
Density of air depends on pressure and temperature (which vary with elevation), but we can estimate ρ ≈ 1.21 kg/m³.
For a skydiver falling headfirst, C ≈ 0.7.
Substituting all values:
v = √(2 × 80.0 kg × 9.8 m/s² / (1.21 kg/m³ × 0.7 × 0.140 m²))
v = 115 m/s
v = 115 m/s × (1 km / 1000 m) × (3600 s / hr)
v = 414 km/hr
Answer:
Positive.
Explanation:
As a consequence of the photoelectric effect, electrons that will get hit by sufficiently energetic photons will abandon the metal surfaces exposed to bright sunlight. This decreases the negative charge of the surface, thus causing it to develop a positive net charge.
Solution :
A vector is defined as an element that has magnitude of some measure and direction.
It is given there is vector 'd' which has magnitude 2.6 m and its direction is towards north.
a). -d
The magnitude of the vector '-d' is 2.6 m and its direction is reversed, i.e. its direction is towards south.
b). d/2.0
The magnitude of the vector 'd/2.0' is 1.3 m and its direction is towards north.
c). - 2.5d
The magnitude of the vector increases by 2.5 times i.e. 2.5 x 2.6 = 6.5 m and the direction is towards south.
d). 5.0d
The magnitude of the vector increases by 5 times i.e. 5 x 2.6 = 13 m and the direction is towards north.
A). period is time
b). amplitude can be almost anything that waves . . . length, voltage, pressure, current etc.
But not hertz.
c). frequency ... "oftenness ... reciprocal time. the only item on this list that CAN be measured in Hertz.
d). wavelength ... length units
