A body is projected at 30° with the horizontal. Theair offers res...
Understanding the Problem
When a body is projected horizontally and experiences air resistance proportional to its velocity, the dynamics change from ideal projectile motion.
Analysis of Options
- Option A: The trajectory is a symmetrical parabola
- In ideal projectile motion without air resistance, the trajectory is a parabola. However, with air resistance proportional to velocity, the trajectory becomes asymmetrical.
- Option B: Time of rise equals time of return to the ground
- In the presence of air resistance, the time taken to rise to the maximum height is not equal to the time taken to fall back down, as the body experiences drag on both ascent and descent.
- Option C: Velocity at the highest point is directed along the horizontal
- This statement is correct. At the highest point of the trajectory, the vertical component of the velocity is zero, while the horizontal component remains unaffected by gravitational forces, assuming air resistance is proportional to the velocity. Hence, the velocity vector points horizontally.
- Option D: Sum of kinetic and potential energies remains constant
- This is incorrect because the presence of air resistance means that energy is lost to the environment, hence the total mechanical energy (kinetic + potential) is not conserved.
Conclusion
The correct answer is indeed option C. The velocity at the highest point of the projectile's path, when projected horizontally with air resistance, is directed along the horizontal axis, as the vertical component becomes zero while the horizontal component persists.
A body is projected at 30° with the horizontal. Theair offers res...
C is correct
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