Answers to true or false conceptual questions on projectiles in Physics
and equations of a projectile .
A projectile is launched. Assuming that air resistance is negligible, which of the following are true?
-
Any object upon which the only acting force is the force of gravity is called a projectile.
TRUE: Definition
-
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
-
The vertical component of the velocity of the projectile is constant.
FALSE: see equations of velocity of projectile.
-
The horizontal component of the velocity of the projectile is constant.
TRUE: see equations of velocity of projectile.
-
The acceleration is constant.
TRUE: see equations of acceleration of projectile
-
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.
-
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.
-
The sum of the kinetic and potential energies is constant.
TRUE: The total mechanical energy is constant.
-
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.
-
The horizontal component of the velocity of the projectile varies linearly with time.
FALSE: It is constant.
-
The horizontal component of the displacement of the projectile varies linearly with time.
TRUE: x = Vx t (see equations of displacement of projectile)
-
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)
-
The path of a projectile is a parabola.
TRUE: See equation of the path of a projectile.
