12. A car is travelling at 30 m/s when the driver sees a red light in the distance and immediately applies the brakes. The car c
1 answer:
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The drag force is directly proportional to the square of the velocity of motion of the object. So as the speed is doubled, the magnitude of drag force will get quadrupled.
<u>Explanation: </u>
Drag force is the opposing or resisting force acting on any object by the medium in which it is moving. So in this case, you are riding a bicycle, thus the medium can be considered as air.
The formula for calculating drag force is as below:
Here, ρ is the density of the air molecules, v is the velocity or speed of the bicycle, CD is the drag coefficient and A is the area of the bicycle.
In the above equation, only the term velocity will be a varying quantity with respect to time and other quantities will remain constant throughout the single situation of riding of bicycle.
So, the equation can be,
Where ,
(constant for this whole condition)
Now given the speed of bicycle increased from v to 2v, so the initial drag force will be
After increase in speed, the final drag force will be
Thus, if the speed of the bicycle is doubled, the drag force will get increased by four times.
Answer:a
Explanation:
Given
two bodies are falling with negligible air Resistance and one of the body is given a slight horizontal acceleration
since there is no change in vertical acceleration therefore time taken by both bodies is same irrespective of change in horizontal direction
suppose both start from rest from a height of h
time taken
The only difference is that body with horizontal acceleration will be some distance away from first