Physics Ch. 3
True/False. The horizontal and vertical components of a vector are independent of each other. Explain.
True because a change in the vertical component does not affect the horizontal component and vise versa.
What is a projectile?
Object which the only force acting on it is gravity
What is the prime launch angle of an object for the farthest distance shot? Explain.
45 degrees because when something is shot from a 45 degree angle it goes the farthest because as the degrees increase so will the distance it travels until it hits a certain point when the distances will start to decrease. This point is 45 degrees because it is the exact middle between 0 and 90 degrees.
What is projectile motion?
The motion of a projectile that is thrown near the earth's surface and moves along a curved path under the action of gravity only
What affects the projectile? Explain.
Height and angle projectile is shot from because it affects where it lands.
What are the two components of a vector?
Horizontal and vertical
Vectors are represented by what?
arrows
What is the formula for distance fallen?
d=1/2gt^2 meters
Long range projectiles need to take into account the curvature of the Earth.
if an object is projected far enough, it will fall all the way around Earth and become a satellite
Scalar quantities are specified by only what?
magnitude
What is the process of determining the components of a vector?
resolution
What is used to represent the magnitude and direction of a vector quantity?
Arrow
What is the formula for free fall distance of an object dropped from rest? How does this compare to projectile motion? Explain.
½ gt^2; it is the same for projectile motion because both are only affected by gravity
Give an example of a vector quantity? Why is it considered a vector quantity?
1. movement or motion of a projectile because it is moving in a certain direction and its magnitude can be calculated 2. velocity because the equation to find velocity is distance/time so both magnitude and direction are needed to define it
Projectiles hit the ground with the same speed that they are projected upward with.
?
What is an example of a projectile?
A stone thrown into the air
What is a vector?
Arrow that represents the magnitude and direction of a vector quantity.
A projectile is launched at an angle into the air. Neglecting air resistance, what is its horizontal acceleration? Explain.
Constant because it will go forever if nothing is affecting it such as no gravity
Understand how free fall compares to projectile motion
Free fall can only occur under gravity, but projectile motion can occur under any force field.? • Free fall is a special case of projectile motion where the initial velocity is zero. • Free fall cannot occur in situations where the air resistance is present, but projectile motion can occur in such situations.?
What is acceleration of the horizontal component of velocity? How does it differ from the vertical component?
Horizontal is constant but vertical is not because it is acceleration due to gravity so velocity is not constant
Assuming they are from the same height, will a ball shot at 0 degrees horizontally or a ball dropped from rest hit the ground first?
Horizontal velocity does not affect vertical, so they will fall at the same time
Satellites.....
If object is moving fast enough, it will fall around the Earth instead of into it becoming a satellite; this is called orbit
Is there any situation where the total combined velocity of a projectile can be zero? Why or why not.
No because a projectile will always have horizontal acceleration because it is a constant
Does horizontal component of motion for a projectile depend on the vertical component of motion? Explain.
No because the vertical component of velocity is affected by gravity and it is independent from horizontal
A cannonball shot from a cannon, a stone thrown into the air, a ball rolling off the edge of a table, a spacecraft circling Earth--all of these are examples of ________. Explain why.
Projectiles because they have a horizontal and vertical component and the only force acting on it is gravity.
A cannon fired at 15 degrees and 60 degrees is shot. Which one hits the ground first? Explain why?
The cannon fired at 15 degrees because there is a law of science that states that if two angles add up to 90 degrees the same range is obtained, or they will land in the same spot. However, for these angles they do not add up to 90 so the smaller angle remains in the air for a shorter time.
A projectile will rise to its maximum height in the same time it takes to fall from that height to the ground.
This is due to the constant effect of gravity- deceleration as it goes up is equal to acceleration as it goes down
At the top of its trajectory, only the vertical velocity is momentarily zero.
This is the split second that it changes from going up to going down (it changes direction here; that is why we were able to plug in zero for velocity in order find out when it hit its maximum height in calculus)
What is the difference between a vector quantity and a scalar quantity? Explain.
Vector: magnitude and direction Scalar: just magnitude
Understand how to calculate magnitude and direction angle from given vector quantities
X = mag1 x cos(angle1) + mag2 x cos(angle2) Y = mag1 x sin(angle1) + mag2 x sin(angle2) magnitude is the length of the hypotenuse direction angle is inverse tangent
Does an object shot at 75 degrees have horizontal motion? Explain.
Yes, because its horizontal velocity is a constant nonzero value