2. What is equal to the kinetic energy of a car with a mass of 0.5t (tonne) if it travels

A long, rigid conductor, lying along the x-axis, carries a current of 7.0 A in the negative direction. A magnetic field B is pre

Alisiya [41]

Answer:

0.546 $\hat k$

Explanation:

From the given information:

The force on a given current-carrying conductor is:

$F = I ( \L \limits ^ {\to } \times B ^{\to})\\ \\ dF = I(dL\limits ^ {\to } \times B ^{\to})$

where the length usually in negative (x) direction can be computed as

$\L ^ {\to } = -x\hat i \\dL\limits ^ {\to }- dx\hat i$

Now, taking the integral of the force between x = 1.0 m and x = 3.0 m to get the value of the force, we have:

$\int dF = \int ^3_1 I ( dL^{\to} \times B ^{\to})$

$F = I \int^3_1 ( -dx \hat i ) \times ( 4.0 \hat i + 9.0 \ x^2 \hat j)$

$F = I \int^3_1 - 9.0x^2 \ dx \hat k$

$F = I (9.0) \bigg [\dfrac{x^3}{3} \bigg ] ^3_1 \hat k$

$F = I (9.0) \bigg [\dfrac{3^3}{3} - \dfrac{1^3}{3} \bigg ] \hat k$

where;

current I = 7.0 A

$F = (7.0 \ A) (9.0) \bigg [\dfrac{27}{3} - \dfrac{1}{3} \bigg ] \hat k$

$F = (7.0 \ A) (9.0) \bigg [\dfrac{26}{3} \bigg ] \hat k$

F = 546 × 10⁻³ T/mT $\hat k$

F = 0.546 $\hat k$

4 0

3 years ago

Please answer the question in the picture, worth 25 points

viktelen [127]

Answer:

Option C, increases and decreases

Explanation:

When an object making noise approaches you, the wave frequency increases leading to a higher pitch. Conversely, when it moves away from you or retreats, the wave frequency decreases leading to a lower pitch. This can be observed in ambulance sirens.

5 0

3 years ago

5.<br>why does the pointer rotate?

morpeh [17]

Answer: find the answer in the explanation.

Explanation:

From the experiment set up in the diagram, the pointer is resting on the drinking straw while the rod is resting on the drinking straw.

When the rod is being heated through the bursen burner, there will be linear expansion in the rod. As the rod increases its length, this causes the drinking straw to roll and thereby causing the pointer to rotate.

The pointer therefore rotates because of the thermer expansion that happen in the rod due to the heat from the bursen burner.

8 0

3 years ago

What equation describes conservation of charge?

Phantasy [73]

Answer:

The equation which describes conservation of charge is $Q_{initial} - Q_{final } = 0$

Explanation:

The law of conservation charge states that for an isolated system that sum of initial charges is equal to sum of final charges, that is the total charge is conserved.

let the sum of initial charges = $Q_{initial}$

let the sum of the final charges = $Q_{final}$

$Q_{initial } = Q_{final}\\\\Q_{initial } - Q_{final} = 0$

Therefore, the equation which describes conservation of charge is $Q_{initial} - Q_{final } = 0$

6 0

3 years ago

A NASA explorer spacecraft with a mass of 1,000 kg takes off in a positive direction from a stationary asteroid. If the velocity

Jet001 [13]

Before the launch, the momentum of the (spacecraft + asteroid) was zero. So after the launch, the momentum of the (spacecraft + asteroid) has to be zero.

Momentum = (mass) x (velocity)

Momentum after the launch:

Spacecraft: (1,000 kg) x (250 m/s) = 250,000 kg-m/s

Asteroid: (mass) x (-25 m/s)

Their sum: 250,000 - 25(mass) .

Their sum must be zero, so 250,000 kg-m/s = (25 m/s) x (mass)

Divide each side by 25 : 10,000 kg-m/s = (1 m/s) x (mass)

Divide each side by (1 m/s) : 10,000 kg = mass

3 0

3 years ago

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