Answer:
Explanation:
velocity of sound in air at 20⁰C is 343 m /s
velocity of sound in water at 20⁰C is 1481 m /s
The wavelength of the sound is 2.86 m in the air so its frequency
= 343 / 2.86 = 119.93 .
This frequency of 119.93 will remain unchanged in water .
wavelength in water = velocity in water / frequency
= 1481 / 119.93
= 12. 35 m .
Because it's so much closer to us than any other star.
<span>Mass of rock 1 is m1 = 10 kg Mass of rock 2 is m2 = 20 kg 10-kg rock takes T (the same time ) to reach the ground as similar to 20-kg rock that takes time T to reach the ground. If no air resistance is present, the rate of descent depends only on how far the object has fallen, no matter how heavy the object is. This means that two objects will reach the ground at the same time if they are dropped simultaneously from the same height. This statement follows from the law of conservation of energy and has been demonstrated experimentally by dropping a feather and a lead ball in an airless tube.
When air resistance plays a role, the shape of the object becomes important. THUS 10-KG & 20-KG ROCK reaches the ground in T-time</span>
Answer:
Equal to the weight of the object
Explanation:
There are two forces acting on the object hanging on the string:
- The tension in the string, T, acting upward
- The weight of the object, mg, acting downward
We can write Newton's second law as:
where a is the acceleration of the object.
Here we are told that the elevator is moving at constant speed: this means that the acceleration of the object is zero, therefore a = 0 and the equation becomes
therefore, the tension in the string is equal to the weight of the object.
