Conceptual Question on Projectile Motion

[Raios168]

Homework Statement

Question says there is a car moving at 2 m/s and a projectile is launched from top of the car at a speed of 7 m/s relative to the car. They give the angle as 25 degrees above the horizontal but then ask what is the angle that it makes with ground when it finally lands? My first thought was that it would be the same as the launching angle since it would follow a parabolic path, but the answer to the question is not 25 degrees. So why is this the case, what am I not understanding?

To put it simply, if a projectile is launched from ground level at an angle theta then will it have that same angle when it lands? Thanks in advance.[/B]

 

[CWatters]

It's because the car is moving. Imagine if the car was moving very fast horizontally (say 1000m/s). When it hit the ground the horizontal velocity of the projectile would also be very high (compared to the vertical velocity which is unchanged) so the angle would be very shallow.

If the car was going backwards at just the right speed the projectile would land vertically :-)

 

[Raios168]

Awesome, I understand it now. Thank you very much