Answer:
0.85m
Explanation:
Given parameters:
Height of fall = 3.5m
Unknown:
Duration of fall = ?
Solution:
To solve this problem, we apply the right motion equation.
Since we know the height, we can use the equation below;
S = ut + 
S is the height
u is the initial velocity = 0m/s
t is the time
g is the acceleration due to gravity
3.5 = 0 + 
x 9.8 x t²
3.5 = 4.9t²
t² = 
t² = 0.71
t = √0.71 = 0.85m
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.
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Answer:
5.65 times
Explanation:
60 db sound is equal to 60 phons sound when frequency is kept at 1000Hz.
But when the frequency of sound is changed to 100 Hz , according to equal loudness curves , the loudness level on phon scale will be 35 phons.
A decrease of 10 phon on phon- scale makes sound 2 times less loud
Therefore a decrease of 25 phons will make loudness less intense by a factor equal to 2²°⁵ or 5.65 less intense . Therefore intensity at 100 Hz
must be increased 5.65 times so that its intensity matches intensity of 60 dB sound at 1000 Hz frequency.
The heat flows into the sample in the segment <u> BC </u> will yield the value of the heat of fusion of this substance.
<h3>Heat of fusion:</h3>
The heat of the fusion of water is unusually high. The amount of heat required to convert 1 g of solid into a liquid while maintaining the same temperature is known as the heat of fusion. It is a latent heat as well and is occasionally referred to as the latent heat of fusion. Since water only freezes at a single temperature (0 °C), it only has one value, which is 79.71 cal/g, or the rounded amount of 80 cal/g.
In order to control frost, water fuses at a high temperature. The water used for irrigation is frequently consistently above freezing when it is extracted from the ground.
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Answer:
The motion of the lighter child would look faster than that of the heavier child, but both have the same period of oscillation.
Explanation:
Oscillation is a type of simple harmonic motion which involves the to and fro movement of an object. The oscillation takes place at a required time called the period of oscillation.
Since the swings are similar, the period of oscillation of the two children are the same and they would complete one oscillation in the same time. Though the oscillation of the lighter child seems faster than that of the heavy child, their masses does not affect the period of oscillation.
When a heavy object oscillates, its mass increases the drag or damping force, but not the period of oscillation. Thus, it oscillate slowly.
