Projectile Motion Equations: Checking Answers for Moving Objects

[Melchior25]

Could anyone please double check my answers to each of the following statements. Thanks

Homework Statement

Determine which of the following moving objects obey the equations of projectile motion.

True A stone is thrown under water.
True A ball is thrown in an arbitrary direction.
True A jet airplane crosses the sky with its engines thrusting the plane forward.
True A rocket moves through the sky after its engines have failed.
False A rocket leaves the launch pad.

 

[PhanthomJay]

Could anyone please double check my answers to each of the following statements. Thanks

Homework Statement

Determine which of the following moving objects obey the equations of projectile motion.

True A stone is thrown under water.
True A ball is thrown in an arbitrary direction.
True A jet airplane crosses the sky with its engines thrusting the plane forward.
True A rocket moves through the sky after its engines have failed.
False A rocket leaves the launch pad.

Not all your answers are correct, even when air resistance is neglected (which should have been stated in the problem). Hint: There is only one force acting on an object in ideal projectile motion problems. What is that force? How does it affect your answers?

 

[Moetasim]

I would say that your answers are mostly correct. However, I would like to clarify one point. The statement "A rocket leaves the launch pad" is actually true. The equations of projectile motion can still be applied to this scenario, as the rocket is initially given an upward velocity and then falls back to the ground due to gravity. The only difference is that the rocket is not moving horizontally. Therefore, the equations still hold true.