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3 years ago

10

A runner begins running at the beginning of 7th period and stops running at the end of the period. She runs at a pace of 10 km/h

r and travels 9.2 km. How long did she run

1 answer:

MrRissso [65]3 years ago

8 0

Answer:

She run for, t = 0.92 s

Explanation:

Given data,

The velocity of the runner, v = 10 km/h

The distance covered by the runner, d = 9.2 km

The relationship between the velocity, displacement and time is given by the formula,

t = d / v

Substituting the given values in the above equation,

t = 9.2 / 10

= 0.92 s

Hence, she ran for, t = 0.92 s

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A box-shaped metal can has dimensions 5 in. by 19 in. by 4 in. high. All of the air inside the can is removed with a vacuum pump

GuDViN [60]

Answer:

The force is $F = 1397 lb$

Explanation:

From the question we are told that

The length of the box is $l = 19 \ in$

The width of the box is $w = 5 \ in$

The height is $h = 4\ in$

The pressure experience on one of the sides is mathematically represented as

$p = \frac{F}{A}$

Where A is the area of the box which is mathematically evaluated as

$A = l * w$

substituting values

$A = 5 *19$

$A = 95 \ in^2$

This pressure is equivalent to the atmospheric pressure which has a constant value of $p = 14.7 pi$

This implies that

$14.7 = \frac{F}{95}$

=> $F = 14.7 *95$

=> $F = 1397 lb$

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3 years ago

A factory worker pushes a 32.0 kg crate a distance of 7.0 m along a level floor at constant velocity by pushing horizontally on

g100num [7]

Answer:

(a) 81.54 N

(b) 570.75 J

(c) - 570.75 J

(d) 0 J, 0 J

(e) 0 J

Explanation:

mass of crate, m = 32 kg

distance, s = 7 m

coefficient of friction = 0.26

(a) As it is moving with constant velocity so the force applied is equal to the friction force.

F = 0.26 x m x g = 0.26 x 32 x 9.8 = 81.54 N

(b) The work done on the crate

W = F x s = 81.54 x 7 = 570.75 J

(c) Work done by the friction

W' = - W = - 570.75 J

(d) Work done by the normal force

W'' = m g cos 90 = 0 J

Work done by the gravity

Wg = m g cos 90 = 0 J

(e) The total work done is

Wnet = W + W' + W'' + Wg = 570.75 - 570.75 + 0 = 0 J

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3 years ago

The water flowing through a 2.0 cm (inside diameter) pipe flows out through three 1.3 cm pipes. (a) If the flow rates in the thr

Verdich [7]

Answer:

a)54L/min

b)0.845

Explanation:

a) A x V= $A_1V_1+ A_2V_2+A_3V_3$

where suffix 1,2,3 refers to the three pipes.

=27L/min+16L/min+11 L/min

=54L/min

b) A x V=54L/min => $\frac{\pi }{4} d^2$ x v

d= 2 cm

$\frac{\pi }{4} d^2$ x v = 54

v= $\frac{4}{\pi }$ x $\frac{54}{2^2}$

-> $A_1$ x $V_1$ =27L/min => $\frac{\pi }{4} d_1^2$ x $v_1$

$d_1$ = 1.3cm

$\frac{\pi }{4} d^2$ x $v_1$ = 27

$v_1$ = $\frac{4}{\pi }$ x $\frac{27}{1.3^2}$

Next is to find the ratio of speed i.e $\frac{v}{v_1}$

$\frac{4}{\pi }$ x $\frac{54}{2^2}$ / $\frac{4}{\pi }$ x $\frac{27}{1.3^2}$ => $\frac{54}{27}$ $\frac{1.3^2}{2^2}$

$\frac{v}{v_1}$ = 0.845

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dusya [7]

Answer: direct linear

Explanation:

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gayaneshka [121]

Answer:

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Explanation:

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3 years ago