Explanation:
The speed of a wave is given by :
......(1)
(i) Here, the wavelength of a sound wave in air reduces by a factor of 3. Equation (1) becomes :

Wavelength and frequency are inversely proportional to each other. So, if wavelength of a sound wave in air reduces by a factor of 3, then the frequency will increases by a factor of 3.
(ii) It remains the same.
Answer:
(a)0.0675 J
(b)0.0675 J
(c)0.0675 J
(d)0.0675 J
(e)-0.0675 J
(f)0.459 m
Explanation:
15g = 0.015 kg
(a) Kinetic energy as it leaves the hand

(b) By the law of energy conservation, the work done by gravitational energy as it rises to its peak is the same as the kinetic energy as the ball leave the hand, which is 0.0675 J
(c) The change in potential energy would also be the same as 0.0675J in accordance with conservation law of energy.
(d) The gravitational energy at peak point would also be the same as 0.0675J
(e) In this case as the reference point is reversed, we would have to negate the original potential energy. So the potential energy as the ball leaves hand is -0.0675J
(f) Since at the maximum height the ball has potential energy of 0.0675J. This means:
mgh = 0.0675
0.015*9.81h = 0.0675
h = 0.459 m
The ball would reach a maximum height of 0.459 m
Answer:
The net force acting on this object is 180.89 N.
Explanation:
Given that,
Mass = 3.00 kg
Coordinate of position of 
Coordinate of position of 
Time = 2.00 s
We need to calculate the acceleration

For x coordinates

On differentiate w.r.to t

On differentiate again w.r.to t

The acceleration in x axis at 2 sec

For y coordinates

On differentiate w.r.to t

On differentiate again w.r.to t

The acceleration in y axis at 2 sec

The acceleration is

We need to calculate the net force



The magnitude of the force


Hence, The net force acting on this object is 180.89 N.
Answer:
What is a Pure Substance?
Explanation:
It is something which cannot be divided into parts by physical means, as it's all made up of the same thing. Pure substances are either elements or compounds. Elements can NOT be separated into other types of matter (physically or chemically).
Another (slightly more technical) name for kidney stones is "renal calculus".
I know this because we have met many times, and we are old friends.