A body is throwmn vertically upwards if air resistance is to be taken ...
If a body is thrown upward its velocity gradually decreases, hence air resistance is less. so time of ascent is less. but when it falls down, its velocity increases and air resistance is more, and more will be time of descent. so the answer is B.
A body is throwmn vertically upwards if air resistance is to be taken ...
Answer:
Introduction: When a body is thrown vertically upwards, it experiences air resistance. The time for which the body rises depends on the air resistance acting on it. In this article, we will discuss whether the time during which the body rises is equal to, less than, greater than, or twice the time of fall when air resistance is taken into account.
Explanation:
- When air resistance is not considered: In the absence of air resistance, the time of rise and fall for a body thrown vertically upwards is equal. This is because the acceleration due to gravity is constant and acts in the same direction throughout the motion of the body.
- When air resistance is considered: When air resistance is taken into account, the time during which the body rises is greater than the time of fall. This is because air resistance opposes the motion of the body when it is moving upwards. As a result, the upward velocity of the body decreases and it takes more time to reach the maximum height.
- Factors affecting the time of rise: The time for which the body rises when air resistance is considered depends on various factors such as:
- The mass of the body
- The cross-sectional area of the body
- The density of the medium through which the body is moving
- The velocity of the body
- Relation between the time of rise and fall: The time during which the body rises is not twice the time of fall. This is because the upward velocity of the body decreases due to air resistance, but the downward velocity of the body increases due to the acceleration due to gravity. As a result, the time of fall is less than the time of rise.
Conclusion:
Therefore, the correct answer to the given question is option (b) less than the time of fall. When air resistance is taken into account, the time during which the body rises is greater than the time of fall. This is because air resistance opposes the upward motion of the body and reduces its upward velocity. However, the time of rise is not twice the time of fall as the downward velocity of the body increases due to the acceleration due to gravity.