Vector B has x, y, and z components 4, 6, and 3, respectively.

13. If a track athlete runs an 800 m race at a constant speed of 2 m/s, how long will it

german

Answer:

A. 6.7 min

Explanation:

3 0

4 years ago

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What types of energy are produced during firework displays?

-Dominant- [34]

Answer: The chemical energy is converted to heat, light ,sound and kinematic movements.

Explanation:

An exploding firework is essentially a number of chemical reactions happening simultaneously or in rapid sequence. When you add some heat, you provide enough activation energy (the energy that kick-starts a chemical reaction) to make solid chemical compounds packed inside the firework combust (burn) with oxygen in the air and convert themselves into other chemicals, releasing smoke and exhaust gases such as carbon dioxide, carbon monoxide, and nitrogen in the process. For example, this is an example of one of the chemical reactions that might happen when the main gunpowder charge burn.

some of the chemical energylocked inside them is converted into four other kinds of energy (heat, light, sound, and the kinetic energy of movement). According to a basic law of physics called the conservation of energy.

8 0

3 years ago

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A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneou

Roman55 [17]

Answer:

The solid sphere will reach the bottom first.

Explanation:

In order to develop this problem and give it a correct solution, it is necessary to collect the concepts related to energy conservation. To apply this concept, we first highlight the importance of conserving energy so we will match the final and initial energies. Once this value has been obtained, we will concentrate on finding the speed, and solving what is related to the Inertia.

In this way we know that,

$\Delta KE = - \Delta PE$

$KE_t + KE_r = mgh$

We know as well that the lineal and angular energy are given by,

$KE_r = \frac{1}{2}I\omega^2$

And the tangential kinetic energy as

$KE_t = \frac{1}{2} mv^2$

Where $\omega = \frac{v}{R}$

Replacing

$\frac{1}{2}mv^2 + \frac{1}{2}I\frac{v}{R} = mgh$

Re-arrange for v,

$v=\sqrt{\frac{2mgh}{m+I/R^2}}$

We have here three different objects: solid cylinder, hollow pipe and solid sphere. We need the moment inertia of this objects and replace in the previous equation found, then,

For hollow pipe:

$I_{hp}=mR^2$

$v_{hp}=\sqrt{\frac{2mgh}{m+(mR^2)/R^2}}$

$v_{hp}=\sqrt{\frac{2mgh}{m+m)}$

$v_{hp}=\sqrt{gh}$

For solid cylinder:

$I_{sc}=\frac{1}{2}mR^2$

$v_{sc}=\sqrt{\frac{2mgh}{m+(1/2mR^2)/R^2}}$

$v_{sc}=\sqrt{\frac{2mgh}{m+1/2m}}$

$v_{sc}=\sqrt{\frac{3}{4}gh}$

For solid sphere,

$I_{ss}=\frac{2}{5}mR^2$

$v_{ss}=\sqrt{\frac{2mgh}{m+(2/5mR^2)/R^2}}$

$v_{ss}=\sqrt{\frac{2mgh}{m+2/5m}}$

$v_{ss}=\sqrt{\frac{10}{7}gh}$

Then comparing the speed of the three objects we have:

$v_{hp}$

$\sqrt{gh}$

3 0

4 years ago

What are the signs of a chemical change

Rom4ik [11]

Gas or bubbles are formed
Heat, light, or sound is given off
Change in color
Different taste or smell (never taste or smell anything in a chemical lab, cause if u do bad reactions may occur to your body, unless directed to do so.)
New substance is formed (a precipitate)
<span>Temperature (exothermic or endothermic reactions) ( exothermic RELEASES heat energy) (endothermic ABSORBS energy)</span>

5 0

3 years ago

A 0.676 m long section of cable carrying current to a car starter motor makes an angle of 57.7º with the Earth’s 5.29 x 10^−5T f

Studentka2010 [4]

Answer:

The current in the wire under the influence of the force is 216.033 A

Solution:

According to the question:

Length of the wire, l = 0.676 m

$\theta = 57.7^{\circ}$