Question

describe the acceleration experiment by astronaut david scott in 1971. get it? identify why is it important to clearly define the coordinate system you want to use when analyzing objects in free - fall? get it? analyze during which second does the rising ball stop and reverse direction? how can you tell? get it? describe if you throw a ball straight up, what would the shape of its position - time graph look like? get it? analyze if you throw a ball straight up, what are its velocity and acceleration at the uppermost point of its path?

Explanation:

Question 1: Describe the acceleration experiment by astronaut David Scott in 1971

In 1971 on the Moon, David Scott dropped a hammer and a feather simultaneously. In the air - less environment of the Moon, without air resistance, both the hammer and the feather fell at the same rate and hit the ground at the same time, demonstrating that in the absence of air - resistance, all objects fall with the same acceleration due to gravity.

Question 2: Why is it important to clearly define the coordinate system you want to use when analyzing objects in free - fall?

A clearly defined coordinate system provides a consistent reference frame. It allows for accurate specification of the position, velocity, and acceleration of the object. Without a well - defined coordinate system, values for position, velocity, and acceleration would be ambiguous, making it impossible to accurately analyze the motion of the object in free - fall.

Question 3: During which second does the rising ball stop and reverse direction? How can you tell?

The rising ball stops and reverses direction at the moment its velocity becomes zero. If we have a velocity - time graph of the ball's motion, the ball stops and changes direction at the instant where the velocity curve crosses the time - axis (v = 0). In terms of a physical experiment, we can observe the ball reaching its maximum height and then starting to fall back down. This occurs when the upward force (initially from the throw) is overcome by the downward force of gravity, causing the ball's upward velocity to decrease to zero.

Question 4: If you throw a ball straight up, what would the shape of its position - time graph look like?

The position - time graph of a ball thrown straight up is a parabola opening downwards. Initially, the ball moves upwards, so the position (height) increases with time. As the ball reaches its maximum height, its velocity becomes zero, and then it starts to fall back down, and the position (height) decreases with time. Using the kinematic equation \(y = y_0+v_0t-\frac{1}{2}gt^2\) (where \(y\) is the position, \(y_0\) is the initial position, \(v_0\) is the initial velocity, \(t\) is time, and \(g\) is the acceleration due to gravity), which is a quadratic equation of the form \(y = at^2+bt + c\) (\(a=-\frac{1}{2}g\), \(b = v_0\), \(c = y_0\)), and the graph of a quadratic function is a parabola.

Question 5: If you throw a ball straight up, what are its velocity and acceleration at the uppermost point of its path?

At the uppermost point of the ball's path, its velocity is zero. This is because the ball has stopped moving upwards and has not yet started moving downwards. The acceleration at the uppermost point is equal to the acceleration due to gravity (\(g\approx9.8m/s^2\) on Earth) and is directed downwards. Gravity is constantly acting on the ball, and even at the instant when the ball's velocity is zero at the maximum height, the gravitational force is still pulling the ball downwards, causing the acceleration.

Answer:

Question 1: In 1971 on the Moon, David Scott dropped a hammer and a feather simultaneously, and they hit the ground at the same time due to the lack of air - resistance.
Question 2: A well - defined coordinate system provides a consistent reference frame for accurate specification of position, velocity, and acceleration.
Question 3: The ball stops and reverses direction when its velocity is zero, which can be seen on a velocity - time graph where the curve crosses the time - axis or in a physical experiment when the ball reaches its maximum height.
Question 4: The position - time graph is a parabola opening downwards.
Question 5: Velocity is 0, acceleration is \(g\) (downwards).