Question

1.
a compressed spring projects a ball horizontally in a vacuum chamber.
on the earth, the ball reaches the chamber floor 4.0 m in front of the spring.
an identical experiment is done on the moon. the gravitational field strength is lower on the
moon than on the earth.
the experimental results on the moon are compared with those on the earth.
which statement is correct?
a the horizontal speed is greater on the moon and the ball hits the floor 4.0 m in front of the
spring.
b the horizontal speed is greater on the moon and the ball hits the floor more than 4.0 m in
front of the spring.
c the horizontal speed is the same on the moon and the ball hits the floor 4.0 m in front of the
spring.
d the horizontal speed is the same on the moon and the ball hits the floor more than 4.0 m in
front of the spring.
2.
diagram 1 shows a piece of flexible material that contains many pockets of air. diagram 2 shows
the same piece of flexible material after it has been compressed so that its volume decreases.

what happens to the mass and to the weight of the flexible material when it is compressed?

3.

Explanation:

Question 1

Step1: Analyze horizontal speed

In a vacuum, there is no air resistance. The horizontal component of velocity remains constant throughout the motion as there is no horizontal force acting on the ball (Newton's first law: \(F = ma\), \(F_{x}=0\) implies \(a_{x} = 0\), and \(v_{x}=v_{0x}\)). So the horizontal speed is the same on the Moon and on the Earth.

Step2: Analyze vertical motion

The vertical motion of the ball is a free - fall motion. The equation for vertical displacement \(y=\frac{1}{2}gt^{2}\). On the Moon, \(g_{Moon}t_{Earth}\).
The horizontal displacement \(x = v_{x}t\). Since \(v_{x}\) is the same and \(t_{Moon}>t_{Earth}\), \(x_{Moon}>x_{Earth}\) (where \(x_{Earth} = 4.0m\))

Step1: Analyze mass

Mass is a measure of the amount of matter in an object. Compressing the material does not add or remove matter. So, by the definition of mass, \(m\) (mass) remains constant.

Step2: Analyze weight

Weight \(W=mg\), where \(m\) is mass and \(g\) is the gravitational field strength. Since \(m\) is constant and \(g\) (assuming we are on the same planet, \(g\) is constant for the experiment location) is constant, \(W\) (weight) remains constant.

Answer:

D. The horizontal speed is the same on the Moon and the ball hits the floor more than 4.0m in front of the spring.

Question 2