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3 years ago

LETS TALK ABOUT ANYTHING!!! IS IT NORMAL TO ALWAYS BE SAD??? like all the time........

Physics

2 answers:

Gennadij [26K]3 years ago

5 0

Umm, not normal or healthy but common
could be depression

Andru [333]3 years ago

5 0

I think it is I’m never happy lol always thinking about sad stuff always feel sad and put on a fake smile so people won’t ask me if I’m okay or not

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AgNO3(aq)+NaCl(aq)—>|NaN03(aq)+AgCl(s)

ASHA 777 [7]

the answer to the question is (D)

8 0

3 years ago

A person uses a surfboard to ride every 30th wave crest towards the beach. The wave crest travels at a speed of 1.6m/s and the d

pashok25 [27]

Answer:

Explanation:

Applying,

v = λf................ Equation 1

Where v = velocity/ speed of the wave, λ = wave length of the wave, f = number of waves the person surf in one seconds.

make f the subject of the equation

f = v/λ............ Equation 2

From the question,

Given: v = 1.6 m/s, λ = 24 m

Substitute these values into equation 2

f = 1.6/24

f = 0.0667 wave/seconds.

If,

in one seconds, the person surf a total wave crest of 0.0667

Therefore,

in one hours, he will surf a total wave crest of (0.0667×60×60) = 240 waves crest

He rides for every 30th wave crest,

Hence,

number of wave crest the person surf in one hour = 240/30 = 8

6 0

3 years ago

A ball is hit 1 meter above the ground with an initial speed of 40 m/s. If the ball is hit at an angle of 30 above the horizonta

Vika [28.1K]

Answer:

$t_t=4.131\ s$

Explanation:

Given:

height above the horizontal form where the ball is hit, $y=1\ m$

angle of projectile above the horizontal, $\theta=30^{\circ}$

initial speed of the projectile, $u=40\ m.s^{-1}$

Firstly we find the vertical component of the initial velocity:

$u_y=u.\sin\theta$

$u_y=40\times \sin30^{\circ}$

$u_y=20\ m.s^{-1}$

During the course of ascend in height of the ball when it reaches the maximum height then its vertical component of the velocity becomes zero.

So final vertical velocity during the course of ascend:

$v_y=0\ m.s^{-1}$

Using eq. of motion:

$v_y^2=u_y^2-2g.h$ (-ve sign means that the direction of velocity is opposite to the direction of acceleration)

$0^2=20^2-2\times 9.8\times h$

$h=20.4082\ m$ (from the height where it is thrown)

Now we find the time taken to ascend to this height:

$v_y=u_y-g.t$

$0=20-9.8t$

$t=2.041\ s$

Time taken to descent the total height:

we've total height, $h'=h+y$ $=20.4082+1$

$h'=u_y'.t'+\frac{1}{2} g.t'^2$

during the course of descend its initial vertical velocity is zero because it is at the top height, so $u_y'=0\ m.s^{-1}$

$21.4082=0+4.9t'^2$

$t'=2.09\ s$

Now the total time taken by the ball to hit the ground:

$t_t=t'+t$

$t_t=2.09+2.041$

$t_t=4.131\ s$

3 0

3 years ago

What are the factor that affect the efficiency of a pulley

alukav5142 [94]

Answer:

Tension in the chains - In a chain drive, technically, you have a closed-chain (which has no end) going around 2 pulley or gears; looking closely you have 2 parallel chains going in opposite direction. If kept in horizontal direction, the one below the other is the slack side and the other the tight side. The tension on the upper or tight side is more than the slack side. So you need to keep in mind to keep your chain drive tight so that there is no loss or rotation or lags.

Sizes of the pulley/gear - The chain will be warped around a pair of pulley or gear. The sizes of these pulley/gear will also determine the efficiency of the chain drive (consider one big and one small)

Number of pulley/gear - If the number of pulley/gear is more and chain wrapped on it with little complexity will result in decrease in efficiency because of extra tension.

Length of the chain drive - You cannot have much too long chain drive. It will make your slack side more heavy because the end are further away. You have to apply more power and possibilities of lag increases decreasing efficiency. In an ideal situation, this won't happen, but this world isn't ideal.

Friction between chains & pulley/gear - If you have studied gears (involving its teeth), you will come to know that there is friction offered on the two meeting surfaces.

Angle of contact - This would have been explained better with a diagram. Although, if you are familiar with the terms you won't have difficulty understanding. Angle of contact is the angle the chain forms with the pulley/gear at the point of contact with the center of the pulley. The angle of contact should not be too small, or else the things will be slippery.

Explanation:

8 0

4 years ago

If you push a box across the floor, the box experiences what kind of friction?

Talja [164]

I think it is kinetic friction not the best at physics

4 0

3 years ago

Read 2 more answers