Answer:
Average velocity of an object is equal to the instantaneous velocity when it's acceleration is zero.
Explanation:
Answer:
Power_input = 85.71 [W]
Explanation:
To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.
![W = F*d](https://tex.z-dn.net/?f=W%20%3D%20F%2Ad)
where:
W = work [J] (units of Joules)
F = force [N] (units of Newton)
d = distance [m]
We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.
Now replacing:
![W = (80*10)*3\\W = 2400 [J]](https://tex.z-dn.net/?f=W%20%3D%20%2880%2A10%29%2A3%5C%5CW%20%3D%202400%20%5BJ%5D)
Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.
![P=\frac{W}{t}](https://tex.z-dn.net/?f=P%3D%5Cfrac%7BW%7D%7Bt%7D)
where:
P = power [W] (units of watts)
W = work [J]
t = time = 40 [s]
![P = 2400/40\\P = 60 [W]](https://tex.z-dn.net/?f=P%20%3D%202400%2F40%5C%5CP%20%3D%2060%20%5BW%5D)
The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.
![Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}=60/0.7\\P_{introduced}=85.71[W]](https://tex.z-dn.net/?f=Effic%3D0.7%5C%5CEffic%3DP_%7Brequired%7D%2FP_%7Bintroduced%7D%5C%5CP_%7Bintroduced%7D%3D60%2F0.7%5C%5CP_%7Bintroduced%7D%3D85.71%5BW%5D)
The final velocity of the bullet+block is 0.799 m/s
Explanation:
We can solve this problem by applying the principle of conservation of momentum: in fact, the total momentum of the bullet-block system must be conserved before and after the collision.
Mathematically, we can write:
![mu+MU=(m+M)v](https://tex.z-dn.net/?f=mu%2BMU%3D%28m%2BM%29v)
where
m = 0.001 kg is the mass of the bullet
u = 800 m/s is the initial velocity of the bullet
M = 1 kg is the mass of the block
U = 0 is the initial velocity of the block (initially at rest)
v is the final combined velocity of the bullet and the block
Solving the equation for v, we find the final velocity:
![v=\frac{mu}{m+M}=\frac{(0.001)(800)}{0.001+1}=0.799 m/s](https://tex.z-dn.net/?f=v%3D%5Cfrac%7Bmu%7D%7Bm%2BM%7D%3D%5Cfrac%7B%280.001%29%28800%29%7D%7B0.001%2B1%7D%3D0.799%20m%2Fs)
Learn more about conservation of momentum:
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<h2>The temperature of the air is 66.8° C</h2>
Explanation:
From the Newton's velocity of sound relationship , the velocity of sound is directly proportional to the square root of temperature .
In this case The velocity of sound = frequency x wavelength
= 798 x 0.48 = 383 m/sec
Suppose the temperature at this time = T K
Thus 383 ∝
I
The velocity of sound is 329 m/s at 273 K ( given )
Thus 329 ∝
II
Dividing I by II , we have
= ![\sqrt{\frac{T}{273} }](https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7BT%7D%7B273%7D%20%7D)
or
= 1.25
and T = 339.8 K = 66.8° C
Glass has a <u>grater </u>index of refraction than air. The glass's and air's indexes of refraction will be 1.5 and 1, respectively.
<h3>What is an index of refraction?</h3>
The refractive index of a substance is a dimensionless quantity that specifies how quickly light passes through it in optics.
The index of refraction of the glass and air will be 1.5 and 1 respectively.
Hence,glass has a <u>grater </u>index of refraction than air.
To learn more about the index of refraction, refer to the link;
brainly.com/question/23750645
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