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3 years ago

A machine that changes only the direction of a force has a mechanical advantage of

Physics

2 answers:

8090 [49]3 years ago

5 0

Answer:

Explanation:

The word "only"= one!

gogolik [260]3 years ago

4 0

Answer:

the correct answer is 1.

Explanation:

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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

The requirements for a master’s degree in psychology generally include

erastova [34]

It takes 2 years of graduate study in a subfeild, practicum experience, and a thesis.
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6 0

3 years ago

Calculate the translational speed of a cylinder when it reaches the foot of an incline 7.05 mm high. Assume it starts from rest

mestny [16]

Height is 7.05 m and not 7.05 mm

Answer:

9.603 m/s

Explanation:

We are dealing with rotation, so velocity of centre of mass is given by;

v_cm = Rω

Since we are working with a solid cylinder, moment of inertia of the cylinder is; I = ½mR²

Since it is rolled from the top to the bottom, at the top it will have potential energy(mgh) while at the bottom it will have kinetic energy (rotational plus translational kinetic energy).

Using conservation of energy, we have:

P.E = K.E_t + K.E_r

Formula for rotational and kinetic energy here are;

K.E_t = ½mv²

K.E_r = ½Iω²

mgh = ½mv² + ½Iω²

Since we want to find translational speed(v), let's get rid of ω.

Earlier, we saw that v_cm = Rω

Thus; ω = v/R

Also, we know that I = ½mR².

Thus;

mgh = ½mv² + ½(½mR²)(v/R)²

This gives;

mgh = ½mv² + ¼mv²

Divide through by m to get;

gh = v²(½ + ¼)

gh = ¾v²

Making v the subject gives;

v = √(4gh/3)

v = √((4 × 9.81 × 7.05)/3)

v = 9.603 m/s

6 0

3 years ago

1) The energy held in the molecules that your lunch is composed of

Rasek [7]

Answer:

Chemical energy

Explanation:

The energy held in the foods molecules a lunch pack is composed of is chemical energy.

They occur within food substances which originates from plants and animals as giant organic molecules.

Since food is often derived from plants and animals.
Plants produce their own food by producing macromolecules from simple inorganic substances in the environment.
Animals takes up these food and build their own body through it.
Plants and animal parts constitutes organic molecules in which chemical energy is duly stored.
When the molecules are broken down, they released their chemical potential energy into heat energy.

4 0

3 years ago

A 1.5-kg block slides at rest starts sliding down a snow-covered hill Point A, which has an altitude of 10 m. There is no fricti

damaskus [11]

Answer:

the speed of the block when it reaches point B is 14 m/s

Explanation:

Given that:

mass of the block slides = 1.5 - kg

height = 10 m

Force constant = 200 N/m

distance of rough surface patch = 20 m