Answers to true or false conceptual questions on projectiles in Physics and equations of a projectile .

1. Any object upon which the only acting force is the force of gravity is called a projectile.
   
   TRUE: Definition
   
   
2. The projectile problem involves constant velocity along the horizontal direction and constant acceleration along the vertical direction.
   
   TRUE: see equations of velocity and acceleration of projectile
   
   
3. The vertical component of the velocity of the projectile is constant.
   
   FALSE: see equations of velocity of projectile.
   
   
4. The horizontal component of the velocity of the projectile is constant.
   
   TRUE: see equations of velocity of projectile.
   
   
5. The acceleration is constant.
   
   TRUE: see equations of acceleration of projectile
   
   
6. The kinetic energy of the projectile is constant.
   
   FALSE: The magnitude of the velocity of a projectile is not constant, therefore its kinetic energy is not constant.
   
   
7. The potential energy of the projectile is constant.
   
   FALSE: The height of the projectile changes and therefore the potential energy due to gravitation in not constant.
   
   
8. The sum of the kinetic and potential energies is constant.
   
   TRUE: The total mechanical energy is constant.
   
   
9. The minimum speed of the projectile is equal to horizontal component of the velocity of the projectile.
   
   TRUE: The velocity has two components: Vy and Vx. Vx is constant and Vy is a function of time and may be zero.
   
   
10. The horizontal component of the velocity of the projectile varies linearly with time.
    
    FALSE: It is constant.
    
    
11. The horizontal component of the displacement of the projectile varies linearly with time.
    
    TRUE: x = Vx t (see equations of displacement of projectile)
    
    
12. The vertical component of the displacement of the projectile varies linearly with time.
    
    FALSE: y = Vy t - (1/2) g t² (see equations of displacement of projectile)
    
    
13. The path of a projectile is a parabola.
    
    TRUE: See equation of the path of a projectile.