C. FM radio waves is the answer.
Answer:
t = 6.68 seconds
Explanation:
The acceleration of the automobile, 
Initial speed of the automobile, u = 91 km/hr = 25.27 m/s
Final speed of the automobile, v = 104 km/hr = 28.88 m/s
Let t is the time taken to accelerate from u to v. It can be calculated as the following formula as :


t = 6.68 seconds
So, the time taken by the automobile to accelerate from u to v is 6.68 seconds. Hence, this is the required solution.
The area-
The area under the line in a velocity-time graph represents the distance travelled. To find the distance travelled in the graph above, we need to find the area of the light-blue triangle and the dark-blue rectangle.
<span><span>Area of light-blue triangle -
<span>The width of the triangle is 4 seconds and the height is 8 meters per second. To find the area, you use the equation: <span>area of triangle = 1⁄2 × base × height </span><span>so the area of the light-blue triangle is 1⁄2 × 8 × 4 = 16m. </span></span></span><span> Area of dark-blue rectangle
The width of the rectangle is 6 seconds and the height is 8 meters per second. So the area is 8 × 6 = 48m.</span><span> Area under the whole graph
<span>The area of the light-blue triangle plus the area of the dark-blue rectangle is:16 + 48 = 64m.<span>This is the total area under the distance-time graph. This area represents the distance covered.</span></span></span></span>
Explanation:
The two postulates of special theory of relativity
Postulate 1: The law of physics are invariant under any of inertial frame of reference.
Postulate 2: The velocity of light is remains same in each ans every frame of reference and independent of relativity.
They are differ from classical mechanics that in classical mechanics there is no change in mass and length in relative velocity but in relativistic mechanics it changes.
These two postulates implements in phenomenon like time dilation , length contraction etc.
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