Answer:
0.119 s
Explanation:
Given that
Lets take final speed of the softball after covering 4.8 m = V
We know that
Also We know that
Putting the value of V ,U and a in the previous equation We get
Therefore slide time will be 0.119 s
A) Jaką długość powinien mieć mieć bok kwadratu , aby pole tego kwadratu było równe polu prostokątu o wymiarach 3cm x 4
1 answer:
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Answer:
A) mass = 3121.58 kg
B) tension = 25940.37 N
C) tension = 25940.37 N (tension on both sides will be the same)
Explanation:
Weight of elevator = 22500 N
Distance = 6.75 m
Time = 3 sec
Since it started from rest, initial speed is zero.
Using Newton's equation of motion we have,
S = ut + 0.5at^2
S = distance covered = 6.75 m
t = time = 3 s
a = acceleration upwards
u = initial velocity = 0
Substituting values, we have,
6.75 = 0(3) + (0.5 x a x 3^2)
6.75 = 4.5a
a = 6.75/4.5 = 1.5 m/s^2 (acceleration of the elevator upwards)
Mass of the elevator = Weight/g
Where g = acceleration due to gravity 9.81 m/s
Mass = 22500/9.81 = 2293.58 kg
From the image below we solve from
T - 22500 = ma
T - 22500 = 2293.58 x 1.5
T - 22500 = 3440.37
T = 3440.37 + 22500 = 25940.37 N (this is the tension on the rope)
On the other side,
mg - T = ma
9.81m - 25940.37 = 1.5m
(9.81 - 1.5)m = 25940.37
8.31m = 25940.37
m = 3121.58 kg (mass of counter weight)
See image below
(a) -83.6 Hz
Due to the Doppler effect, the frequency of the sound of the train horn appears shifted to the observer at rest, according to the formula:
where
f' is the apparent frequency
v = 343 m/s is the speed of sound
is the velocity of the source of the sound (positive if the source is moving away from the observer, negative if it is moving towards the observer)
f is the original frequency of the sound
Here we have
f = 350 Hz
When the train is approaching, we have
So the frequency heard by the observer on the platform is
When the train has passed the platform, we have
So the frequency heard by the observer on the platform is
Therefore the overall shift in frequency is
And the negative sign means the frequency has decreased.
(b) 0.865 m
The wavelength and the frequency of a wave are related by the equation
where
v is the speed of the wave
is the wavelength
f is the frequency
When the train is approaching the platform, we have
v = 343 m/s (speed of sound)
f = f' = 396.7 Hz (apparent frequency)
Therefore the wavelength detected by a person on the platform is