Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum

Initial kinetic energy

Final kinetic energy

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
Answer:
(a) The ratio of the pressure amplitude of the waves is 43.21
(b) The ratio of the intensities of the waves is 0.000535
Explanation:
Given;
density of gas,
= 2.27 kg/m³
density of liquid,
= 972 kg/m³
speed of sound in gas,
= 376 m/s
speed of sound in liquid,
= 1640 m/s
The of the sound wave is given by;

Where;
is the pressure amplitude

(b) when the pressure amplitudes are equal, the ratio of the intensities is given as;

Answer:
<h3>The answer is 2.5 g/cm³</h3>
Explanation:
The density of a substance can be found by using the formula

From the question we have

We have the final answer as
<h3>2.5 g/cm³</h3>
Hope this helps you
The train is moving at 50 m/s and Emma is walking down the aisle with 1 m/s speed in the same direction of train. The relative velocity of Emma with respect to other passengers pf the train would be 1 m/s. This is because, the train is not moving relative to them and only emma is moving at 1 m/s. If a person observes from outside, Emma would have (50 +1) m/s = 51 m/s velocity.
relative velocity when two objects are moving in same direction as oberved from outside observer:

relative velocity when two objects are moving in the opposite directionas oberved from outside observer:
