The first thing we must do for this case is the sum of forces in a horizontal direction.
We have then:
Substituting values we have:
From here, we clear the mass of the object:
We now look for the weight of the object.
Where,
g: acceleration of gravity (9.8 m/s^2)
Substituting values:
Answer:
the weight of the object is:
option 4
Answer: send the message underwater because a more dense medium would make the sound travel faster.
Explanation:
Dolphins communicate using compression waves - longitudinal waves. Longitudinal waves requires a medium to travel. A longitudinal wave transfers energy by the vibration of medium particles in the direction of the wave motion. Compression are the regions where density of the medium is higher and rarefaction is a low density region.
A longitudinal wave travels faster in a denser medium. It has maximum speed in solid and minimum in gas. Thus, to transfer message quickly to dolphin B., dolphin A should send the message underwater and not in air. This is because water has higher density than air. Molecules collide more quickly in water than in air and it takes less time for signal to travel.
The correct answer is
<span>c) very small and very large
Let's see this with a few examples:
1) if we have a very small number, such as
</span>
<span>we see that we can write it easily by using the scientific notation:
</span>
<span>2) Similarly, if we have a very large number:
</span>
<span>we see that we can write it easily by using again the scientific notation:
</span>
<span>
</span>
Answer:
(A) Q = 321.1C (B) I = 42.8A
Explanation:
(a)Given I = 55A−(0.65A/s2)t²
I = dQ/dt
dQ = I×dt
To get an expression for Q we integrate with respect to t.
So Q = ∫I×dt =∫[55−(0.65)t²]dt
Q = [55t – 0.65/3×t³]
Q between t=0 and t= 7.5s
Q = [55×(7.5 – 0) – 0.65/3(7.5³– 0³)]
Q = 321.1C
(b) For a constant current I in the same time interval
I = Q/t = 321.1/7.5 = 42.8A.
