Answer:
<em>down, backwards, and outwards.</em>
Explanation:
For a hornet that is accelerating in flight, this means that there is a net forward motion at a relatively constant vertical height above the ground.
For this flight, the <em>wings beat downwards to counter the weight of the hornet due to gravity</em>, keeping it at that height above the floor.
For the hornet to accelerate forward, there has to be a net backwards force by the wing on the air. This backwards force accelerates tr forward due to the absence of an equal opposing force in the opposite direction save for a little drag.
The wings also beat with forces directed outwards to provide centripetal force to keep the hornet stable. <em>The absence of this would cause it to spiral out of control.</em>
<em>Something is missing in question. But I will try to explain you about Doppler effect to reach your answer.</em>
Answer:
- It is defined as "an increase in the frequency of sound, light or other waves as the source or observer moves towards each other".
- This effect causes the sudden change in pitch noticeable in passing siren.
- You hear a siren from a few blocks away. The source is a police car that is racing in your direction. As the car approaches, zooms past you, and then speeds off into the distance, the sound of its siren keeps changing in pitch. First the siren gets higher in pitch, and then it suddenly gets lower.
Answer:
a) Ktotal = 71.85 J
b) Ktotal = 71.85 J
Explanation:
a) The total kinetic energy is that of the total mass of the bicycle plus the rotational kinetic energy of the two wheels. The linear speed of the circumference of the wheels matches the forward speed of the bicycle, so their angular speed is
ω = v/r
The moment of inertia of one solid disk bicycle wheel is
I = 0.5*m₂*r²
And the rotational kinetic energy of one wheel is
Kr = 0.5*I*ω² = 0.5*(0.5*m₂*r²)*(v/r)² = 0.25*m₂*v²
The total kinetic energy is then that of the frame and wheels plus the rotational kinetic energy.
Ktotal = 0.5*(m₁ + 2*m₂)*v² + 2*(0.25*m₂*v²)
⇒ Ktotal = 0.5*v²*(m₁ + 3*m₂)
where
m₁ = 6.75 Kg
m₂ = 0.820 kg
v = 3.95 m/s
then
⇒ Ktotal = 0.5*(3.95 m/s)²*(6.75 Kg + 3*0.820 kg)
⇒ Ktotal = 71.85 J
b) We can apply the same equation obtained before
⇒ Ktotal = 0.5*v²*(m₁ + 3*m₂)
where
m₁ = 675 Kg
m₂ = 82.0 kg
v = 0.395 m/s
then
⇒ Ktotal = 0.5*(0.395 m/s)²*(675 Kg + 3*82 kg)
⇒ Ktotal = 71.85 J
<span>d. the conversion of kinetic energy created by the movement of gasses into a useful form of energy</span>
Answer:
See below
Explanation:
100 km / 45 km/hr = 2.222 hr
100 km / 30 km/hr =3.3333 hr
Difference = 1.111 hr = 1 hr 6 2/3 min
