1.
What determines the maximum height of an object following a parabolic trajectory?
Correct Answer
D. Both A and B
Explanation
Both A and B. The maximum height of an object following a parabolic trajectory is determined by both its initial speed and the angle at which it is launched.The initial speed provides the object with the kinetic energy needed to reach a certain height. The faster the object is moving at the beginning, the higher it can potentially go.The angle of launch affects how much of that initial speed is directed upwards, against the force of gravity. A launch angle close to 90 degrees (straight up) will result in the greatest height for a given initial speed. However, if the angle is too shallow, much of the initial speed is directed horizontally, and the object will not reach as high of a maximum height.Therefore, to achieve the maximum height for a parabolic trajectory, both the initial speed and the angle of launch must be considered and optimized.
2.
Which factor does not affect the range of a projectile in ideal conditions (no air resistance)?
Correct Answer
C. Mass of the projectile
Explanation
Mass of the projectile. In ideal conditions with no air resistance, the range of a projectile is not affected by its mass. The range is determined by the launch speed, launch angle, and the acceleration due to gravity, which remains constant for all objects near the Earth's surface. Increasing the launch speed or adjusting the launch angle can increase the range of the projectile. However, the mass of the object does not play a role in determining how far it will travel in ideal conditions. This principle can be understood through the basic equations of projectile motion, which do not include mass as a variable.
3.
What is the shape of the trajectory for a projectile launched in a vacuum near the Earth's surface?
Correct Answer
B. Parabolic
Explanation
Parabolic. In a vacuum near the Earth's surface, where gravity is the only significant force acting on a projectile, the trajectory of a launched object will follow a parabolic path. This shape emerges from the combination of the constant acceleration due to gravity acting downwards and the initial velocity of the projectile, which can be resolved into horizontal and vertical components. The horizontal velocity remains constant while the vertical velocity changes due to gravity, creating the characteristic curved, parabolic path. In real-world situations with air resistance, the trajectory may deviate from a perfect parabola due to additional drag forces acting on the object, but in a vacuum, the ideal parabolic shape is preserved.
4.
At what angle should a projectile be launched to achieve maximum range in a vacuum?
Correct Answer
B. 45 degrees
Explanation
45 degrees. To achieve the maximum range for a projectile launched in a vacuum, the optimal angle is 45 degrees relative to the ground. This angle provides the ideal balance between the horizontal and vertical components of the initial velocity, allowing the projectile to travel the farthest distance before returning to the same height from which it was launched. At angles greater or less than 45 degrees, either the horizontal or vertical component of velocity will be reduced, resulting in a shorter range. This principle can be mathematically demonstrated using the equations of projectile motion, which show that the maximum range is achieved when the launch angle is 45 degrees.
5.
If the initial velocity is doubled, how does the range of a projectile change, assuming no air resistance?
Correct Answer
D. Quadruples
Explanation
Quadruples. If the initial velocity of a projectile is doubled while maintaining the same launch angle and in the absence of air resistance, the range of the projectile will increase by a factor of four, or quadruple. This result can be understood by examining the equation for the range of a projectile, which is directly proportional to the square of the initial velocity (R ∝ v^2). By doubling the initial velocity, the kinetic energy of the projectile increases fourfold, leading to a significantly greater range. This principle is an important aspect of projectile motion and can be applied to various scenarios, from sports to aerospace engineering, where maximizing the range of a projectile or an object's flight is desired.
6.
What component of the initial velocity is responsible for the maximum height reached by a projectile?
Correct Answer
B. Vertical velocity
Explanation
Vertical velocity. The maximum height reached by a projectile is determined by its vertical velocity, specifically the initial upward velocity imparted to the object when it is launched. The greater the upward or positive vertical velocity at the start, the higher the maximum height the projectile will attain. As the object travels upward, gravity acts to slow its ascent until it momentarily stops at its maximum height before beginning its descent. In contrast, the horizontal velocity does not affect the maximum height, as it only influences how far the object will travel horizontally during its flight. The total velocity, which combines the horizontal and vertical components, is also not directly responsible for determining the maximum height achieved by the projectile.
7.
During the motion of a projectile, when is the vertical velocity zero?
Correct Answer
D. At the maximum height
Explanation
At the maximum height. During the motion of a projectile, the vertical velocity becomes zero at the maximum height it reaches. This is because, as the object travels upward, gravity exerts a constant downward force on it, causing it to slow down and eventually come to an instantaneous stop before it begins its descent. At the moment when the object reaches its maximum height, the upward force imparted by the initial launch exactly balances the downward force of gravity, resulting in a vertical velocity of zero. Once this point is reached, the object's velocity in the upward direction decreases, and it starts to fall back towards the ground due to gravity's influence.
8.
Which equation is not directly used to calculate any aspect of a parabolic trajectory?
Correct Answer
C. F=ma
Explanation
F=ma is not directly used to calculate any aspect of a parabolic trajectory. This equation relates the force acting on an object (F) to its mass (m) and acceleration (a). In the case of a parabolic trajectory, the primary focus is on the object's motion and position, rather than the force causing that motion. The acceleration due to gravity is considered constant, and the other equations of motion are utilized to analyze and describe various aspects of the trajectory, such as maximum height, range, and flight time.
9.
What happens to the time of flight if the launch angle of a projectile is increased from 30 degrees to 45 degrees?
Correct Answer
A. Increases
Explanation
Increases. When the launch angle of a projectile is increased from 30 degrees to 45 degrees, the time of flight increases. The time of flight refers to the total time the object remains in the air before returning to the same height from which it was launched. A greater launch angle results in a larger vertical component of initial velocity, causing the object to reach a higher maximum height. This increased height leads to a longer time for the object to ascend, as well as a longer time to descend back to its initial height. In the case of a 45-degree launch angle, the time of flight is at its maximum for any given initial velocity, as this angle optimizes the balance between the horizontal and vertical components of the initial velocity, leading to the greatest time spent in the air.
10.
Which of the following is a true statement about a projectile's acceleration during its flight in a vacuum?
Correct Answer
C. It remains constant at g downwards.
Explanation
It remains constant at g downwards. In a vacuum, the acceleration of a projectile during its flight remains constant at g, which is the acceleration due to gravity. This value is approximately 9.8 m/s^2 downwards on Earth's surface. Regardless of the object's initial velocity and launch angle, gravity constantly acts on the object, pulling it downwards at a consistent rate. This constant acceleration is what gives the trajectory its parabolic shape, as the object's vertical velocity changes while its horizontal velocity remains constant. At the peak of the trajectory, the object's vertical velocity momentarily becomes zero, but its acceleration due to gravity remains the same, causing it to begin its descent back to the ground.