Answer:
Explanation:
The momentum of a body is defined as the product of its mass and its velocity at a given time. Therefore the change in the momentum of the ball is given by the difference between the final momentum and the initial momentum:
Preventing projects
1 answer:
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The amount of work which Sam does need to stop the boat is 784Joule if boat mass is 800kg and boat drift in 1.4m/sec.
We know that according to work-energy theorem, change in kinetic energy of the body from one speed to another is equivalent to amount of work done by all forces acting on the body.
So, here we can see that final speed of boat is =0m/sec since Sam need to stop it.
Initial speed of boat is 1.4m/sec.
Also, we know that kinetic energy is given by the below formula:
Kinetic energy=(1/2)mv²
where m is the mass of the body
and v is the speed of the body
Now, from work energy theorem, we get
=>W=(1/2)m - (1/2)m
=>W=0-(1/2)×800×(1.4)²
=>W= - 400× 1.4 × 1.4
=>W = -400×1.96
=>W= -784Joule
Here negative sign denotes work has to done against the original motion of boat.
Hence, amount of work needs to be done by Sam is 784Joule.
To know more about work,visit here:
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Answer:
The frequency increases, and the pitch increases
Explanation:
- Doppler's law of sound is applicable in such case when the observer or the sound source or both are moving relative to each other.
- In such a case due to space-time constraint the waveform of the sound adjust themselves so as to obey the law of conservation of energy.
<u>The apparent frequency of the sound for the observer is given by:</u>
....................................(1)
where:
observed frequency
original source frequency
speed of sound
speed of source relative to the observer (taken negative when approaching towards the observer and vice-versa)
speed of observer relative to the source (taken negative when moving away from the source and vice-versa)
<u>According to the given situation, eq. (1) becomes:</u>
Since,
Therefore
Pitch is very closely related to the frequency, it means that how fast is the amplitude of sound varying with time.