lab 3 Projectile 2D motion Flashcards
An object is considered to be in free fall if
An object is considered to be in free fall if it is in the air, and not under any external force except for gravity.
We will be ignoring the effect of
air resistance for this experiment.
Free fall does not necessarily mean that an
object is moving downwards – when an object is launched upward, as we will see in this experiment, it is considered to be in free fall the moment it loses contact with the external force that is propelling it. One example is throwing a ball, where the moment the ball leaves your hand it can be considered to be in free fall, even if it is thrown directly upward.
An object that is in free fall is only under the influence of gravitational force, and so it has a
constant acceleration due to gravity:
If air resistance is ignored, this is true independently of the object’s mass, size or shape! In a vacuum it can be shown that a bowling ball and a feather will fall with the
same acceleration, as shown in figure 1.
In order to study the 2-dimensional motion of objects in free fall, it is useful to separate the horizontal and vertical components of motion. This leads to
2 sets of kinematic formulas, which are connected only by their time variable (t) but are otherwise mathematically independent.
A football was thrown with an initial speed of 20 m/s at an angle of 30° with the horizontal. What was the magnitude of its vertical acceleration after 2 seconds?
9.8 m/s2
Two projectiles are both launched with initial speeds of 100 m/s, the angle of launch for the first being 30° and for the second 60°. Which of the following statements is NOT true?
The first projectile will stay in air longer than the second one
What is the shape of the trajectory (path) of a projectile?
Parabolic
Which statement is NOT true about a projectile?
The horizontal component of a projectile’s motion is uniformly accelerated.
Based on the simulation, for a given initial speed, which of the following angle of launch produced the longest range?
45
Based on the simulation, for a given initial speed, which of the following angle of launch produced the least time of flight?
25
Which variable will not produce a change in the range of a projectile thrown horizontally?
The mass of the projectile
Which of the following is a valid reason for why the Predicted Range you calculated is not the same as the Measured Range which resulted from the simulation?
The presence of air resistance
A rock is projected horizontally with an initial speed of 2.50 m/s from the edge of a cliff 15.0 m high. How long does it take the rock to hit the ground?
1.75 s
