The guy below is wrong!

F=ma
Where force = mass x acceleration

We dont have acceleration, a= change in velocity divided by the time taken.
a = v (final velocity) - u (initial) / t
a us 8-0 (at rest means u was 0) / 20 = 0.4

Using F=ma

F= mass x acceleration
F= 4 x 0.4
F=1.6 N

5 0

3 years ago

A resistor with r = 340 ω and an inductor are connected in series across an ac source that has voltage amplitude 490 v. The rate

Arada [10]

The value of impedance Z of the circuit, when the rate at which electrical energy is dissipated in the resistor is 316 w, is 508 ohms.

<h3>What is impedance Z of the circuit?</h3>

The impedance Z of the circuit is the ratio of voltage amplitude to the maximum current.

$Z=\dfrac{V}{I}$

Here, V is voltage amplitude and I maximum current.

A resistor with R = 300 Ω and an inductor are connected in series across an ac source that has voltage amplitude 490V. The rate at which electrical energy is dissipated in the resistor is 316 W.

The rate at which electrical energy is dissipated in the resistor is the product of the resistance and the square of current. Thus,

$316=340\times I^2\\I=\sqrt{\dfrac{316}{340}}\\I=0.964\rm\; A$

The impedance Z of the circuit is,

$Z=\dfrac{V}{I}\\Z=\dfrac{490}{0.964}\\Z=508\rm\; ohm$

Thus, the value of impedance Z of the circuit, when the rate at which electrical energy is dissipated in the resistor is 316 w, is 508 ohms.

Learn more about the impedance Z of the circuit here:

brainly.com/question/24225360

#SPJ4

5 0

2 years ago

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small

ahrayia [7]

Let l = Q/L = linear charge density. The semi-circle has a length L which is half the circumference of the circle. So w can relate the radius of the circle to L by

C = 2L = 2*pi*R ---> R = L/pi 

Now define the center of the semi-circle as the origin of coordinates and define a as the angle between R and the x-axis. 

we can define a small charge dq as 

dq = l*ds = l*R*da 

So the electric field can be written as: 

dE =kdq*(cos(a)/R^2 I_hat + sin(a)/R^2 j_hat) 

dE = k*I*R*da*(cos(a)/R^2 I_hat + sin(a)/R^2 j_hat) 

E = k*I*(sin(a)/R I_hat - cos(a)/R^2 j_hat) 

E = pi*k*Q/L(sin(a)/L I_hat - cos(a)/L j_hat)

8 0

3 years ago

Which of the following BEST explains how good body composition is attained?

Nonamiya [84]

Answer:

C. balancing the amount of energy that is taken in with the amount of energy that is released by the body

Explanation:

im smart

6 0

3 years ago