In the following circuit (Fig.3), calculate the intensity I through the resistance 3 using the principle of superposition.

A car of mass m accelerates from speed v_1 to speed v_2 while going up a slope that makes an angle theta with the horizontal. Th

Karo-lina-s [1.5K]

Answer:

Work done by external force is given as

$Work_{external} = mgLsin\theta + \mu mgLcos(\theta) + \frac{1}{2}mv_2^2 - \frac{1}{2}mv_1^2$

Explanation:

As per work energy Theorem we can say that work done by all force on the car is equal to change in kinetic energy of the car

so we will have

$Work_{external} + Work_{gravity} + Work_{friction} = \frac{1}{2}mv_2^2 - \frac{1}{2}mv_1^2$

now we have

$W_{gravity} = -mg(Lsin\theta)$

$W_{friction} = -\mu mgcos(\theta) L$

so from above equation

$Work_{external} - mgLsin\theta - \mu mgLcos(\theta) = \frac{1}{2}mv_2^2 - \frac{1}{2}mv_1^2$

so from above equation work done by external force is given as

$Work_{external} = mgLsin\theta + \mu mgLcos(\theta) + \frac{1}{2}mv_2^2 - \frac{1}{2}mv_1^2$

8 0

3 years ago

Describe the phenomenon of lightning?

masha68 [24]

Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions in the atmosphere or ground temporarily equalize themselves, causing the instantaneous release of as much as one gigajoule of energy.

3 0

3 years ago

How can a megaphone used by a cheerleader allow people on the opposite side of a field to hear her better?

Goshia [24]

The megaphone is cupping the area around her mouth and it is like with your hands, if you cover around them the noise will be louder. It is because it is hollow and there isn't anything to block the noise through the megaphone.

7 0

2 years ago

How might the rate of conduction be affected if the fiber absorbs moisture ?

vlabodo [156]

Answer:

Moisture absorbed by fabric material in a humidity environment or liquid water ... Perspired moisture penetrating into the hydrophobic fiber can increase ... Moisture content within the porous insulating materials greatly affect thermal ... When the ambient humidity increase or decrease

Explanation:

5 0

2 years ago

The angle between vector A = 2.00i + 3.00j and vector B is 45.0°. The scalar product of vectors A 12) and B is 7.00. If the x-co

mario62 [17]

Answer:

B = 2.67i - 0.53j

Explanation:

In order to find the vector B, you first take into account the following formula:

$\vec{A}\cdot\vec{B}=ABcos\theta$ (1)

where:

A = 2.00i + 3.00j

B = ?

θ: angle between vectors A and B = 45.0°

You use the fact that the dot product between vectors A and B is 7.00.

You calculate the magnitude of A vector as follow:

$A=\sqrt{(2.00)^2+(3.00)^2}=3.60$

Then, you solve the equation (1) for the magnitude of B:

$B=\frac{\vec{A}\cdot\vec{B}}{Acos\theta}=\frac{7.00}{3.60cos(45\°)}=2.74$

Next, you can consider that the A vector is the x axis of the coordinate system, to calculate the components of B. This means that the coordinate system is rotated an angle equivalent to the angle of A respect to the x axis.

With the previous assumption you have that the components of B are:

$B_x=Bcos\theta=(2.74)cos45\°=1.93\\\\B_y=Bsin45\°=(2.74)sin45\°=1.93$

The vector B is:

B = 1.93i + 1.93j

Next, it is necessary to rotate again the coordinate system to its original position. For that, you calculate the angle of A:

$\alpha=tan^{-1}(\frac{3.00}{2.00})=56.30$

In order to calculate the real components of B, you rotate the system 56.30°, by using the following relation:

$B_x'=B_xcos\alpha+B_ysin\alpha\\\\B_x'=1.93cos(56.30\°)+1.93sin(56.30\°)=2.67\\\\B_y'=-B_xsin\alpha+B_ycos\alpha\\\\B_y'=-1.93sin(56.30\°)+1.93cos(56.30\°)=-0.53$

The vector B is:

B = 2.67i - 0.53j

7 0

2 years ago