ANSWER
625 m/s
EXPLANATION
Given:
• The frequency of the sound wave, f = 250 Hz
,
• The wavelength, λ = 2.5 m
Find:
• The speed of the wave, v
The speed of a wave of wavelength λ and frequency f is given by,
Substitute the known values and solve,
Hence, the speed of the wave is 625 m/s.
<h2>
Answer: 540 J</h2>
Explanation:
The Work 
done by a Force 
refers to the release of potential energy from a body that is moved by the application of that force to overcome a resistance along a path.
Now, when the applied force is constant and the direction of the force and the direction of the movement are parallel, the equation to calculate it is:
(1)
In this case both (the force and the distance in the path) are parallel (this means they are in the same direction), so the work performed is the product of the force exerted to push the box 
by the distance traveled 
.
Hence:
(2)
Answer:
MATERIAL MEDIUM
Explanation:
Wave is a disturbance that travels through a medium and transfer energy from one point to another without causing any permanent displacement of the medium itself. The two forms of wave are the mechanical wave and the electromagnetic waves.
Mechanical wave is a wave with requires MATERIAL MEDIUM for its propagation. This means that before wave can be propagated at times, material medium is needed e.g a ripple tank. A ripple tank is a mechanical device that generates waves using an instrument called stroboscope attached to it. This kind of wave requires an external source before it can propagate compared to electromagnetic waves that does not require material medium for its propagation.
Answer:
The waves are traveling in a speed of
v=1.20 m/s
Explanation:
The fisherman see a wave at 6m apart so that's the wavelength
Now the period is the time between two successive waves so
The velocity of the waves is describe by:
Answer:
Given:
Mass = 20 kg
Acceleration = 2.5 m/s²
Explanation:
Force = mass × acceleration
= 20 × 2.5
= 50 kg m/s² or 50 N
