Answer:
the state of giving off light or glow.
Answer:
120°
Explanation:
Draw a free body diagram. There are three forces acting on the traffic light. Two tension forces acting along the cables, and weight.
The tension forces have an angle θ between them. That means each tension force forms an angle of θ/2 with respect to the vertical. So the y component of each tension force is:
Ty = T cos (θ/2)
Sum of the forces in the y direction:
∑F = ma
Ty + Ty − W = 0
2 Ty = W
Substituting:
2 T cos (θ/2) = W
If W = T, then:
2 W cos (θ/2) = W
2 cos (θ/2) = 1
cos (θ/2) = 1/2
θ/2 = 60°
θ = 120°
Answer: 1.77 m/s²
Explanation: acceleration is expressed in:
a= ∆v / t = vf-vi/t
a= 18.8 m/s - 0 / 10.6 s
a= 1.77 m/s²
Answer:
D) The velocity of the airplane must be greater than the speed of sound
Explanation:
Sonic boom is a phenomenon that occurs when an airplane travels ay a velocity greater than the speed of sound.
When this condition is met, the sound waves produced by the airplane (mainly from the engine) is not able to travel ahead of the plane, because the plane is moving at a greater speed than the sound itself; as a result, it is only transmitted behind the plane.
In this situation, a shock wave is produced. This shock wave is associated with a very loud "bang", that can be heard clearly even at several kilometers distance (in fact, supersonic planes are normally not allowed to fly over residential areas. In the past, for example the Concorde, was only allowerd to fly at supersonic speed over the ocean).
So the correct answer is
D) The velocity of the airplane must be greater than the speed of sound
