2. Which of the following examples does not show projectile motion?
A. a tennis ball bounces across the net
B. a ball is thrown at a downward angle toward a target on the
ground
C. a feather drifts to the ground
D. a horseshoe is pitched at a stake
Is it C?
3. Which of the following examples shows
parabolic motion?
A. the ball in an extra point kick
B. an apple falling from a tree branch
C. a spacecraft orbiting a planet
D. a model rocket fired vertically into still air
Is it A?
4. Assuming a projectile travels at a constant
velocity and does not hit another object, the
horizontal distance traveled in a given amount of
time is
A. equal to its velocity multiplied by the time
of travel.
B. dependent on the angle at which it was
launched.
C. reduced by the force of gravity, and the
reduction is proportional to the time of
travel.
D. constant.
Is it C?
6. A person on a moving truck throws a ball straight up into the air. This action is
observed by a person at the side of the road, a person following behind the truck, and a
person in a helicopter directly above the person in the truck. Which observers will
perceive the same motion of the ball?
A. the observer in the helicopter and the person throwing the ball
B. the observer following behind the truck and the person throwing the ball
C. the observer at the side of the road and the person throwing the ball
D. the observer following behind the truck and the observer in the helicopter
Is it B?
7. An airplane is flying north at a constant velocity relative to Earth when it encounters a
wind blowing from the east. As a result, the velocity of the airplane relative to
A. Earth increases.
B. Earth decreases.
C. Earth remains the same.
D. the wind decreases.
Is it A?
4. Horizontal component of velocity, u, is CONSTANT D
I agree with the rest, although it does not say what the helicopter is doing. If it were also following like the truck, then both the truck and the helicopter would see up and down.
2. The example that does not show projectile motion is C. A feather drifting to the ground. In order to determine this, we need to understand what projectile motion is. Projectile motion is the motion of an object that is launched at an angle to the horizontal and moves along a curved path under the influence of gravity alone. In option C, the feather is drifting to the ground without any initial launch or curved path, so it does not demonstrate projectile motion.
3. The example that shows parabolic motion is B. An apple falling from a tree branch. Parabolic motion is the motion of an object that follows a curved path in the shape of a parabola. When an apple falls from a tree, it follows a curved path due to the force of gravity, making it an example of parabolic motion.
4. The correct answer is D. The horizontal distance traveled by a projectile is constant, assuming it travels at a constant velocity and does not hit any other objects. This is because the horizontal velocity of a projectile remains unchanged throughout its motion. Option A is incorrect because the horizontal distance is not equal to the velocity multiplied by the time of travel, it is constant. Option B is incorrect because the horizontal distance is not dependent on the angle at which it was launched, but rather the initial velocity. Option C is incorrect because the force of gravity does not affect the horizontal distance traveled by a projectile.
6. The observers that will perceive the same motion of the ball are A. the observer in the helicopter and the person throwing the ball. This is because the ball's motion is independent of the motion of the truck or any other external observer. The ball follows a parabolic trajectory, and as long as the observers are stationary relative to the ball, they will perceive the same motion.
7. The velocity of the airplane relative to Earth increases. When the airplane encounters a wind blowing from the east, it means the wind is acting in the opposite direction of the airplane's motion. As a result, the wind acts as an additional force on the airplane, increasing its overall velocity relative to the Earth. Therefore, the correct answer is A.