<h2>
Answer: an underground lake</h2>
Explanation:
In general, sound (mechanical waves) travels faster in solids than in liquids, and faster in liquids than in gases. This is because <u>the speed of the mechanical waves is determined by a relationship between the elastic properties of the medium </u>in which they are propagated and the mass per unit volume of the medium (that is:<u>density</u>).
In other words: The speed of sound varies depending on the medium through which the sound waves travel.
So, if we are told the sound wave initially had a speed of 4,000 m/s and it suddenly decreases to 1,500 m/s, this means the sound waves passed from a solid medium to a liquid medium.
Hence, the correct option is: an underground lake.
A. fixed volume, changeable shape.
Weight = (mass) x (gravity)
70 N = (mass) x (9.8 m/s²)
Divide each side by (9.8 m/s²) , and you have
mass = 70 N / 9.8 m/s² = 7.14 kg.
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Mass on the moon:
Mass doesn't change. It's a number that belongs to the bowling ball,
no matter where the ball goes. If the mass of the bowling ball is 7.14 kg
anywhere, then it's 7.14 kg everywhere ... on Earth, on the moon, on Mars, rolling around in the trunk of my car, or floating in intergalactic space.
However, WEIGHT depends on the gravity wherever the ball happens to be
at the moment.
The acceleration of gravity on the moon is 1.622 m/s².
So the WEIGHT of the ball on the moon is
(7.14 kg) x (1.622 m/s²) = 11.58 Newtons
That's only about 16% of its weight on Earth.
Answer:
4sec
Explanation:
Since we know the initial velocity=0, acceleration = -4; and the displacemnt =14, we use the equation d = vi • t + ½ • a • t2. So, just plug in the values and solve for t in this case it's 4 sec