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gladu [14]
3 years ago
14

Help plsss i need #1

Physics
1 answer:
DENIUS [597]3 years ago
6 0
Speed is  (distance covered) divided by (time to cover the distance).

"Faster" means he covered more distance in less time.

On a graph of distance/time, the speed is the slope of the line,
because the slope of the line is just

                       (change in distance) divided by (change in time) .

In 'A', the runner went to the middle of the track (20 yards)
before the race started.  Then, when the coach fired the pistol,
he took 4 seconds to run the last half of the track. 
The slope is (20 yards) / (4 seconds)  =  5 yards per second.

In 'B', the runner started at the starting line (zero distance), and when the
race started, he ran 30 yards in 4 seconds.
The slope is (30 yards) / (4 seconds)  =  7.5 yards per second.

In 'C', the distance doesn't change at all.  The runner went to the 40-yards
place before anybody started running, and just stayed there.
The slope is (zero) / (4 seconds).  That's zero yards per second. 
The runner is not running at all.  He's just standing there, watching
the other runners run toward him.

In 'D', the runner went to the 20-yard mark before the race started,
just like 'A' did.  When the pistol fired and the clock started, 'A' and 'D'
were both standing there, and started running.
'D' only ran 10 yards in the whole 4 seconds.
'B' got there at the same time that 'D' did, but 'B' ran 40 yards,
and 'D' only ran 10 yards.
The slope of 'D' is (10 yards) / (4 seconds)  =  2.5 yards per second.
 
Graph 'B' is the steepest line, and that means the fastest speed.

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natulia [17]

Answer:

 x = 25 / μ     [ ft]

Explanation:

To solve this exercise we can use Newton's second law.

Let's set a reference system where the x axis is parallel to the road

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       N_B + N_A = W_van + W_load

X axis

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     a = fr / m

the total mass is

        m = (W_van + W_load) / g

the friction force has the expression

      fr = μ N_{total}

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we substitute

      a = μ (W_van + W_load)    \frac{g}{W_van + W_load}

      a = μ g

taking the acceleration let's use the kinematic relations where the final velocity is zero

       v² = v₀² - 2 a x

       0 = v₀² -2a x

        x = \frac{v_o^2}{2a}

        x = \frac{v_o^2}{2 \mu g}

        x = \frac{40^2}{2 \ 32 \  \mu}

        x = 25 / μ     [ ft]

5 0
3 years ago
If four students separately measure the density of a rock, and they all have very low percent
lesya692 [45]

Answer:

Their measured results are closer to the exact or true value. Hence, their measured value is considered to be more accurate.

Explanation:

Considering the situation described above, the accuracy of a measured value depicts how closely a measured value is to the accurate value.

Hence, since the students' measured values have very low percent differences, it shows the similarity of computations or estimates to the actual values, which in turn offers a smaller measurement error.

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Answer: 1100 ft lb/s and 2 H.P

Explanation:

To calculate for the power developed in the elevator motor in ft.lb/s, we multiply the distance and the weight of the elevator and divide the product by the time.

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