Answer:
a.87.6 m/s
b.18.25 Hz
Explanation:
the equation for the wave speed is expressed as
where v is the speed,
T is the tension in Newton
l is the length
and m is the mass
Now since
by substituting values into the equation, we have
b. the expression for the frequency is giving as
.
Note we 2L as the wavelength because we solving for the fundamental frequency as stated in the question.
Answer:Racquet force is twice of Player force
Explanation:
Given
ball arrives at a speed of
ball returned with speed of
average Force imparted by racquet on the ball is given by
where
time of contact of ball with racquet
When it land on the player hand its final velocity becomes zero and time of contact is same as of racquet
From 1 and 2 we get
Hence the magnitude of Force by racquet is twice the Force by player
Explanation:
- Newton's first law of motion:
"An object at rest (or in uniform motion) remains at rest (or in uniform motion) unless acted upon an unbalanced force
In this situation, we can apply Newton's first law to the keys of the keyboard that are not hit by the fingers of the man. In fact, as no force act on the keys, they remain at rest.
- Newton's second law of motion:
"The acceleration experienced by an object is proportional to the net force exerted on the object; mathematically:
where F is the net force, m is the mass of the object, and a its acceleration"
In this case, we can apply Newton's second law to the keys of the keyboard that are hit by the man: in fact, as they are hit, they experience a downward force, and therefore they experience a downward acceleration.
"Newton's third law of motion:
"When an object A exerts a force on an object B (action force), then object B exerts an equal and opposite force on object A (reaction force)"
Here We can apply Newton's third law to the pair of objects finger-key: in fact, as the finger apply a force on the key (action force), then the key exerts a force back on the finger (reaction force), equal and opposite.