Projectile Motion

At the top of a projectile's path above Earth, the vertical acceleration of an object is

• is zero
• goes from positive to negative
• goes from negative to positive
• remains unchanged

A baseball was thrown with an initial velocity of 24m/s at an angle above the horizontal.  It remained in the air for 2 seconds.  Which of the following quantities was constant while the baseball was in the air?

• acceleration
• displacement
• position
• velocity

A ball is thrown horizontally from the top of a building with an initial velocity of 13m/s.  At the same time, a second ball is dropped from the top of the same building.  Which of the following is the same for the two balls?

• Their final displacement
• Their paths as they fall
• Their initial horizontal velocities
• Their final vertical velocity as they reach the ground

Which of the following shapes is seen in the path of  a projectile?

• straight line
• parabola
• circle
• hyperbola

If you shoot a gun and at the same time drop a bullet which will hit the ground first? Why?

• The bullet that is shot, because it is going faster
• The dropped bullet, because gravity pulls on it.
• At the same time, because the x and y components are independent of each other. 
• This cannot happen

The initial velocity of a projectile has a horizontal component of 5m/s and a vertical component of 6m/s.  At the highest point of the projectile's trajectory what is (A) the horizontal velocity (B) the vertical velocity?

• (A)25m/s, (B) 10m/s
• (A) 5m/s,  (B) 0m/s
• (A) 10m/s, (B) 24m/s
• (A) 0m/s, (B) 3m/s

If I throw a crayon straight up at 12 m/s, how fast is its velocity when I catch it at the same height?

• -6 m/s
• -12 m/s
• -18 m/s
• -24 m/s

What is the horizontal acceleration of a projectile?

• 0 m/s²
• -9.8 m/s²
• 0 m/s
• -9.8 m/s

Which of the following would NOT be considered a projectile? 

• a cannonball thrown straight up
• a cannon ball rolling down a slope
• a cannonball rolling off a table
• a cannonball thrown in the air

What can you say about motion in the x and y direction?

• x is dependent on y
• y is dependent on x
• They are dependent on each other.
• They are independent of each other.