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?