Determine which of the following moving objects obey the equations of projectile motion developed in this topic. A ball is thrown in an arbitrary direction. A jet airplane crosses the sky with its engines thrusting the plane forward. A rocket leaves the launch pad. A rocket moves through the sky after its engines have failed. A stone is thrown under water.

A ball is thrown in an arbitrary direction and a rocket moves through the sky after its engines have failed.

Explanation:

The concept applied is that of projectile motion which is the free fall for both then horizontal and vertical component of a constant velocity. it is also the motion of an object thrown under the influence of acceleration due to gravity.

The correct option are as follows ; A ball is thrown in an arbitrary direction and a rocket moves through the sky after its engines have failed.

For the first case ; A ball is thrown in an arbitrary direction ; after the ball must have been thrown, the projectile further moves in a curved path.

for the second case ; A rocket moves through the sky after its engines have failed ; the rocket also moves in a curved path under the influence of the acceleration due to gravity.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west