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3 years ago

How do you know if a reaction is endothermic?

2 answers:

6 0

Endothermic is when heat is absorbed, so like when ice turns into water, it absorbed heat and energy from the air because now the molecules in the ice started moving faster and more freely to become a liquid state.

AysviL [449]3 years ago

6 0

In an endothermic reaction heat is used up.
So you would know it is endothermic if there is less heat after the reaction than the heat before the reaction.
Or you could just see if there is a heat use up

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The old-fashioned record player had two speeds: one for long-playing albums (LP) and one for singles. The turntable speed for LP

eimsori [14]

Answer:

$\alpha = 0.305 rad/s^2$

Explanation:

initial frequency of revolution is given as

$f_1 = 100/3 rpm$

now initial angular speed is

$\omega_i = 2\pi f$

$\omega_i = 2\pi(\frac{100}{3\times 60})$

$\omega_i = 3.49 rad/s$

Similarly final angular speed is given as

$\omega_f = 2\pi f_2$

$\omega_f = 2\pi(\frac{45}{60})$

$\omega_f = 4.71 rad/s$

Now angular acceleration is given as

$\alpha = \frac{\omega_f - \omega_i}{\Delta t}$

$\alpha = \frac{4.71 - 3.49}{4}$

$\alpha = 0.305 rad/s^2$

3 0

3 years ago

A telephone pole has three cables pulling as shown from above, with F⃗ 1=(300.0iˆ+500.0jˆ) , F⃗ 2=−200.0iˆ , and F⃗ 3=−800.0jˆ .

Ray Of Light [21]

A) Net force in component form: $F=100.0i-300.0j$

B) Magnitude of the net force: 316.2, direction: $-71.6^{\circ}$

Explanation:

The three forces given in this problem are:

$F_1=300i+500j$

$F_2=-200i$

$F_3=-800 j$

The three forces are given in component form, where the components with unit vector i is the component along the x-direction, while the components with unit vector j is the component along the y-direction.

In order to find the net force in component form, we just need to add the components of the three forces along each direction. Therefore:

- Along the x-direction:

$F_x = F_{1x}+F_{2x}+F_{3x}=300+(-200)+0=100$

- Along the y-direction:

$F_y=F_{1y}+F_{2y}+F_{3y}=500+0+(-800)=-300$

So, the net force in component form is

$F=100.0i-300.0j$

The magnitude of a vector F is given by Pythagorean's theorem:

$|F|=\sqrt{F_x^2+F_y^2}$

where in this problem,

$F_x=100$ is the x-component

$F_y=-300$ is the y-component

Substituting,

$|F|=\sqrt{(100)^2+(-300)^2}=316.2$

The direction instead is given by

$\theta=tan^{-1}(\frac{F_y}{F_x})=tan^{-1}(\frac{-300}{100})=-71.6^{\circ}$

where the negative sign means the direction is below the positive x-axis.

Learn more about vector addition:

brainly.com/question/4945130

brainly.com/question/5892298

#LearnwithBrainly

8 0

3 years ago

The blade of a windshield wiper moves through an angle of 90.08 in 0.40 s. The tip of the blade moves on the arc of a circle tha

oksian1 [2.3K]

Answer:

The centripetal acceleration is 6.95 m/s²

Explanation:

Given;

angular displacement of the blade, θ = 90.08⁰

duration of motion of the blade, t = 0.4 s

radius of the circle moved by the blade, r = 0.45 m

The angular speed of the blade in radian is calculated as;

$\omega = \frac{\theta}{t} \times \frac{\pi \ radian}{180^0} \\\\\omega = \frac{90.08 ^0}{0.4 \ s} \times \frac{\pi \ radian}{180^0} \\\\\omega = 3.93 \ rad/s$

The centripetal acceleration is calculated as;

a = ω²r

a = (3.93)² x 0.45

a = 6.95 m/s²

7 0

3 years ago

The force needed to lift an object is equal in size to the gravitational

Elanso [62]

Explanation:

W.D. = F * s = 50N * 2m = 100J.

7 0

3 years ago

(BRAINLIEST!) Does more momentum mean more force?

evablogger [386]

Answer:

no.

Explanation:

5 0

3 years ago