A golf ball is hit into the air, but not straight up, and encounters no significant air resistance.
Which statements accurately describe its motion while it is in the air?
A.On the way up it is accelerating upward, and on the way down it is accelerating downward.
B.On the way up, both its horizontal and vertical velocity components are decreasing; on the way down, they are both increasing.
C.Its vertical acceleration is zero at the highest point.
D.Its horizontal velocity does not change once it is in the air, but its vertical velocity does change.
I hope you can see that on the way up it's decelerating and on the way down it's accelerating. Therefore there should be some point where the acceleration is stationary or 0.
A. How can it accelerate going against gravity?
B. How can the horizontal component be decreasing?
C. What do you think?
D. The horizontal component should be constant if air resistance is ignored. I'll let you finish examining this answer.
Please post some work. I don't see how you're helped just by copying and pasting here.
mv^2
To answer the given question, we can analyze each statement individually:
A. On the way up it is accelerating upward, and on the way down it is accelerating downward.
To understand this statement, we need to remember that acceleration is the rate of change of velocity. While the golf ball is in the air, it experiences the force of gravity, which causes it to decelerate on the way up and accelerate on the way down. This is because gravity is constantly acting downwards and opposes the motion of the ball when it goes up, and aids the motion when it comes back down. So, Statement A is accurate.
B. On the way up, both its horizontal and vertical velocity components are decreasing; on the way down, they are both increasing.
This statement is not accurate. The horizontal component of the ball's velocity does not change because there's no force acting on it in the horizontal direction unless influenced by external factors like wind or air resistance. Therefore, the horizontal velocity remains constant throughout the ball's flight, so Statement B is incorrect.
C. Its vertical acceleration is zero at the highest point.
At the highest point of the ball's trajectory, it momentarily comes to a stop before reversing direction and starting to fall back down. At this point, the vertical velocity is zero. However, the acceleration due to gravity remains constant throughout the ball's flight, even at the highest point. Therefore, Statement C is incorrect.
D. Its horizontal velocity does not change once it is in the air, but its vertical velocity does change.
As mentioned earlier, in the absence of external forces like air resistance or wind, the horizontal velocity of the golf ball remains constant. Once the ball is hit into the air, there are no horizontal forces acting on it to accelerate or decelerate its motion in the horizontal direction. However, the vertical velocity does change due to the influence of gravity, which causes the ball to accelerate downwards. Therefore, Statement D is accurate.
To summarize:
- Statement A is accurate.
- Statement B is incorrect.
- Statement C is incorrect.
- Statement D is accurate.
By analyzing the properties of motion and recalling the effects of gravity and external forces, we can determine which statements accurately describe the golf ball's motion while it is in the air.