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Varvara68 [4.7K]

3 years ago

12

Which of the following activities works on muscle strength? A. cutting hedges B. moving furniture C. raking leaves D. vacuuming

the house

1 answer:

Ksenya-84 [330]3 years ago

3 0

The answer would be B

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Fault block mountains form when large blocks of crust are and tilted along normal faults

Katarina [22]

Fault block mountains form when large blocks of crust are uplifted and tilted along normal faults. The uplifted blocks are called block mountains. They are formed by the movement of large crustal blocks<span> when forces in the Earth's crust pull it apart. Some parts of the Earth are pushed upward and others collapse down.</span>

6 0

3 years ago

A total of 875 J of work was done when a force of 175 N was exerted on a box to move it. How far was the box moved

Vladimir [108]

Work = Force times Distance
W = Fd

Given W = 750J, F = 125N;

750 = 125d

Solving for d:
d = 750/125
d = 6

The box moved a distance of 6 meters.

3 0

2 years ago

2. Find the time taken by the bus to reach the stop. need only group B, 2 answer

Molodets [167]

Answer:

t = 2 seconds

Explanation:

In 2nd question, the question is given the attached figure.

Initial speed of the bus, u = 0

Acceleration of the bus, a = 8 m/s²

Final speed, v = 16 m/s

We need to find the time taken by the car to reach the stop. Acceleration of an object is given by :

$a=\dfrac{v-u}{t}$

t is time taken

$t=\dfrac{v-u}{a}\\\\t=\dfrac{16-0}{8}\\\\t=2\ s$

The bus will take 2 seconds to reach the stop.

3 0

3 years ago

A wind turbine works by slowing the air that passes its blades and converting much of the extracted kinetic energy to electric e

ddd [48]

Answer:

2649600 Joules

Explanation:

Efficiency = 40%

m = Mass of air = 92000 kg

v = Velocity of wind = 12 m/s

Kinetic energy is given by

$K=\frac{1}{2}mv^2\\\Rightarrow K=\frac{1}{2}\times 92000\times 12^2\\\Rightarrow K=6624000\ J$

The kinetic energy of the wind is 6624000 Joules

The wind turbine extracts 40% of the kinetic energy of the wind

$E=0.4\times K\\\Rightarrow E=0.4\times 6624000\\\Rightarrow E=2649600\ J$

The energy extracted by the turbine every second is 2649600 Joules

8 0

3 years ago

An airplane starts from A and flies to B at a constant speed. After reaching B it returns to A at the same speed. There was no w

Dafna1 [17]

Answer:

When there is wind it takes longer

Explanation:

With no wind, the round trip time is

$t_1=\frac{d}{v}+\frac{d}{v}=\frac{2d}{v}$

When we have a constant wind speed w

$t_2=\frac{d}{v-w} +\frac{d}{v+w} =\frac{2vd}{v^{2} -w^{2}}$

comparing the reciprocal times;

$\frac{1}{t_2}=\frac{v^{2}-w^{2} }{2vd}=\frac{v}{2d}-\frac{w^{2}}{2vd} \leq \frac{v}{2d}=\frac{1}{t_1}$

This means that t1 is smaller than t2, ergo, it takes longer with wind

4 0

3 years ago