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elena-14-01-66 [18.8K]

3 years ago

14

Which simple machine is NOT correctly matched with an appropriate task for its use?

1 answer:

Tcecarenko [31]3 years ago

6 0

The simple machine that is not correctly matched with its appropriate task is the inclined plane because there is no such big ramp that is as high as 1 storey building, the appropriate task would be Lifting a heavy box and moving it across a room. and for the pulley : <span>Moving a heavy box up to the second floor of a building.</span>

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At take off a plane flies 100 km north before turning east to fly 200 km east. How far is its destination from where the plane t

andrew-mc [135]

First the plane turns 100 km North, and than 200 km East. Since both the directions are perpendicular to each other, therefore we can apply the Pythagoras theorem to calculate the distance between the destination and the point where plane took off

=100^{2}+200^{2}

D=223.60 km=224 km

Therefore, The destination is 224 km from where the plane took off

8 0

3 years ago

A truck with 0.410 m radius tires travels at 25.0 m/s. What is the angular velocity of the rotating tires in radians per second?

Eduardwww [97]

relation between linear velocity and angular velocity is given as

$v = R\omega$

here

v = linear speed

R = radius

$\omega$ = angular speed

now plug in all data in the equation

$25.0 = 0.410 \omega$

$\omega = \frac{25}{0.410}$

$\omega = 60.9 rad/s$

so rotating speed is 60.9 rad/s

6 0

3 years ago

An extension cord is used with an electric weed trimmer that has a resistance of 17.9 Ω. The extension cord is made of copper (r

Naddika [18.5K]

Answer:

(a) $R_{c}=0.87ohms$

(b) $V_{T}=114.44V$

Explanation:

Part (a)

The total length of copper cord L=86.3 m

The cross sectional area A=1.71×10⁻⁶m²

The resistivity of copper p=1.72×10⁻⁸Ω

Thus the resistance of extension cord is

$R_{c}=p\frac{L}{A}\\R_{c}=(1.72*10^{-8} )\frac{86.3}{1.71*10^{-6}}\\R_{c}=0.87ohms$

Part (b)

The resistance of trimmer Rt=17.9 ohms

When voltage of 120V is applied then the current I is passing through series circuit is

$I=\frac{120V}{R_{c} +R_{T} }\\I=\frac{120V}{0.87 +17.9 } \\I=6.4A$

Thus the voltage across the trimmer is:

$V_{T}=IR_{T}\\V_{T}=(6.4)*(17.9)\\V_{T}=114.44V$

8 0

3 years ago

The wise and careful use of energy resources is calles

soldier1979 [14.2K]

The wise and careful use of energy is called CONSERVATION

4 0

3 years ago

Read 2 more answers

A heat engine does 9200 J of work per cycle while absorbing 22.0 kcal of heat from a hightemperature reservoir. What is the effi

Morgarella [4.7K]

Answer: 9.9%

Explanation: efficiency = (work output /work input) × 100

Note that, 1 kilocalorie = 4184 joules, hence 22kcal = 22× 4184 = 92048 joules.

Work output = 9200 j and work input = 92048 j

Efficiency = (9200/92048) × 100 = 0.099 × 100 = 9.9%

4 0

3 years ago