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3 years ago

A 3.0-kilogram object is placed on a frictionless track at point A and released from rest.

Physics

1 answer:

Eddi Din [679]3 years ago

8 0

Answer:

Explanation:

From the given information:

The gravitational potential energy at A is:

$PE_A = mgh$

GIven that:

mass(m) = 3

height (h) = 3

$PE_A =3\times 9.81 \times 3$

$\mathbf {PE_A =88.29 \ J }$

Using the conservation of mechanical energy:

$PE_A+KE_A = PE_B + KE_B$

$88.29 +0 = 3(9.8)(1) + KE_B$

$88.29 = 29.4 + KE_B$

$KE_B = 88.29 -29.4$

$\mathbf{ KE_B= 58.89 \ J}$

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At one point in the circuit, there is an LED and a resistor in parallel with one another. If you measure the voltage drop across

kifflom [539]

Answer:

C. The voltage drop across the resistor is 2.1V and nothing about the current through the resistor.

Explanation:

When connected in parallel, voltage across the resistances are the same. So if 2.1V was dropped across the LED then 2.1V was also dropped across the resistor. However, this tells us nothing about the current through the resistor. We can find the current across the resistor if we know the resistance of the resistor, but that's about it.

If it were a series connection, then the current would have been the same, but the voltage drop were another story.

7 0

3 years ago

A 0.954-kg toy car is powered by three D cells (4.50 V total) connected directly to a small DC motor. The car has an effective e

Natasha2012 [34]

Answer:

0.06 A

Explanation:

We have given mass =0.954 kg

velocity =1.27 m/sec

efficiency =0.361 the output kinetic energy of the motor $KE=\frac{1}{2}mv^2=\frac{1}{2}\times 0.954\times 1.27^2=0.769\ J$

Efficiency =0.361

so input to the motor = output/efficiency

so input to the motor = $\frac{0.769}{0.361}=2.1301$

we know that $P=\frac{E}{T}$ where E is energy and T is time so $P=\frac{2.1301}{7.88}=0.2703W$

We know that power P=VI we have given V=4.5 VOLT

So current $I=\frac{P}{V}=\frac{0.2703}{4.5}=0.06 A$

3 0

3 years ago

Read 2 more answers

A loop of current-carrying wire has a magnetic dipole moment of 5. 0 10–4 am2. if the dipole moment makes an angle of 57° with a

Digiron [165]

The potential energy will be 1.46*10^-4J.

To find the answer, we have to know about the torque acting on a current loop in a uniform magnetic field.

<h3>How to find the potential energy of the loop?</h3>

We have the expression for torque acting on a current loop in a uniform magnetic field as,

$\tau=MBsin\theta$

where; M is the magnetic dipole moment, B is the magnetic field , and theta is the angle between M and B.

As we know that, the torque is equal to force times the perpendicular distance. Thus, it is equivalent to the work done. This work is stored as the potential energy in the loop.
Thus, the potential energy will be,

$\tau=W=U=MBsin\theta=5*10^{-4}*0.35*sin57=1.46*10^{-4}J$

Thus, we can conclude that, the potential energy will be 1.46*10^-4J.

Learn more about the torque here:

brainly.com/question/27949876

#SPJ4

7 0

2 years ago

Cell phones are technology that is popular throughout the world. Would this technology be of use in rural areas of the world

bonufazy [111]

Unless there is service it wifi, no. To access most features on a cellphone you need wifi or service. These features can include communicating with others or watching a video. Cellphones are practically useless without internet connection.

6 0

3 years ago

Read 2 more answers

What is natural magnets and artificial magnets ? give examples

Luden [163]

NATURAL MAGNETS

A natural magnet is one that occurs naturally in nature. All natural magnet are permanent magnets , meaning they never lose their magnetic power.

Natural magnet can be found in Sandy deposits in various part of the earth .

The strongest natural magnetic material is LODESTONE also called magnetite.

ARTIFICIAL MAGNETS

These are magnets made by people.

It's these magnets that is in our refrigerator doors, which have extra-stronge magnetic power. There are two types of of artificial magnets. Temporary and Permanent Magnets.

Examples of artificial magnets are; electromagnet and the paper clip.

Examples of Permanent Magnets are; Alnico

4 0

3 years ago