Answer:
0°
Explanation:
The angle between force and displacement should be 0° in order to get the maximum work done.
Work done = Force x dcosФ°
Ф is the angle between force and displacement
When Ф is zero, the maximum work done is attained
When Ф is 90, the minimum work is done, in fact, work done is 0
Answer:
9.01amp
Explanation:
Power = V^2/R
Given that v = 11volts, P = 99watts
99 = 11^2/R
11×11 = 99R
121= 99R
R = 121/99
R= 1.22ohms
From ohms Law; V = IR
11volts = I × 1.22ohms
I = 11/1.23
I = 9.01 amp
First we need to find the speed of the dolphin sound wave in the water. We can use the following relationship between frequency and wavelength of a wave:
![v=\lambda f](https://tex.z-dn.net/?f=v%3D%5Clambda%20f)
where
v is the wave speed
![\lambda](https://tex.z-dn.net/?f=%5Clambda)
its wavelength
f its frequency
Using
![\lambda = 2 cm = 0.02 m](https://tex.z-dn.net/?f=%5Clambda%20%3D%202%20cm%20%3D%200.02%20m)
and
![f=22 kHz = 22000 Hz](https://tex.z-dn.net/?f=f%3D22%20kHz%20%3D%2022000%20Hz)
, we get
![v=(0.02 m)(22000 Hz)=440 m/s](https://tex.z-dn.net/?f=v%3D%280.02%20m%29%2822000%20Hz%29%3D440%20m%2Fs)
We know that the dolphin sound wave takes t=0.42 s to travel to the tuna and back to the dolphin. If we call L the distance between the tuna and the dolphin, the sound wave covers a distance of S=2 L in a time t=0.42 s, so we can write the basic relationship between space, time and velocity for a uniform motion as:
![v= \frac{S}{t}= \frac{2L}{t}](https://tex.z-dn.net/?f=v%3D%20%5Cfrac%7BS%7D%7Bt%7D%3D%20%5Cfrac%7B2L%7D%7Bt%7D%20%20)
and since we know both v and t, we can find the distance L between the dolphin and the tuna:
Answer:I need the ans to this one too
Explanation: