Answer:
a) 0.0625 I_1
b) 3.16 m
Explanation:
<u>Concepts and Principles </u>
The intensity at a distance r from a point source that emits waves of power P is given as:
I=P/4π*r^2 (1)
<u>Given Data</u>
f (frequency of the tuning fork) = 250 Hz
I_1 is the intensity at the source a distance r_1 = I m from the source.
<u>Required Data</u>
- In part (a), we are asked to determine the intensity I_2 a distance r_2 = 4 in from the source.
- In part (b), we are asked to determine the distance from the tuning fork at which the intensity is a tenth of the intensity at the source.
<u>solution:</u>
(a)
According to Equation (1), the intensity a distance r is inversely proportional to the distance from the source squared:
I∝1/r^2
Set the proportionality:
I_1/I_2=(r_2/r_1)^2 (2)
Solve for I_2 :
I_2=I_1(r_2/r_1)^2
I_2=0.0625 I_1
(b)
Solve Equation (2) for r_2:
r_2=(√I_1/I_2)*r_1
where I_2 = (1/10)*I_1:
r_2=(√I_1/1/10*I_1)*r_1
=3.16 m
Explanation:
It is given that,
Diameter of the semicircle, d = 45 m
Radius of the semicircle, r = 22.5 m
Speed of greyhound, v = 15 m/s
The greyhound is moving under the action of centripetal acceleration. Its formula is given by :



We know that, 


Hence, this is the required solution.
Answer:
B. W is positive and a is negative
Explanation:
As we know that the angular speed of the second clock is in positive direction so as it comes to halt from its initial direction of motion then we have
initial angular velocity is termed as positive angular velocity

now it comes to stop so angular acceleration is taken in opposite to the direction of angular speed
so we will have

so here correct answer is
B. W is positive and a is negative
Assuming north as positive direction, the initial and final velocities of the ball are:

(with negative sign since it is due south)

the time taken is

, so the average acceleration of the ball is given by

And the positive sign tells us the direction of the acceleration is north.
Answer:
Vp = 1 [m/s]
Explanation:
In order to solve this problem, we must use the principle of conservation of the amount of movement. In the same way, analyze the before and after of the actions.
<u>The moment before</u>
The 50kg person is still hold (no movement) with the 2kg helmet
<u>The moment after</u>
The helmet moves at 25[m/s] in one direction, the person moves in the opposite direction, due to the launch of the helmet.
In this way we can apply the principle of conservation of movement, expressing the before and after. To the left we have the before and to the right of the equal sign we have the after.
Σm*V1 = Σm*V
where:
m = total mass = (2 + 50) = 52[kg]
V1 = velocity before the lunch = 0
(50 + 2)*V1 = (25*2) - (Vp*50)
0 = 50 - 50*Vp
50 = 50*Vp
Vp = 1 [m/s]