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3 years ago

13

A boy rode a bike and covered 90 km at an average speed equals 36 km/h but he covered the first thirty km in two hours. What is

the average speed at which the remaining distance was covered ?

1 answer:

Free_Kalibri [48]3 years ago

3 0

Answer:

40

Explanation:

because his increasing speed

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Nadia drove home while singing with a recording of her favorite songs.This is an example of?(psychology)

lianna [129]

Answer:

Music

Explanation:

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3 years ago

A particle moves along a straight path through displacement while force acts on it. (Other forces also act on the particle.) Wha

allsm [11]

a) c = 1.85

b) c = 0.8

c) c = 2.33

Explanation:

a)

The displacement of the particle is given by

$d=2.2i+cj$

While the force applied on the particle is

$F=3.2i-3.8 j$

So we have a problem in 2-dimensions.

The work done on the particle is given by the scalar product between force and displacement:

$W=F\cdot d$ (1)

Here the work done on the particle is zero, so

W = 0

Therefore from eq(1) we find:

$0=(3.2i-3.8j)\cdot (2.2i+cj)=7.04-3.8c\\3.8c=7.04\\c=\frac{7.04}{3.8}=1.85$

b)

In this problem, the work done on the particle is

$W=4.0 J$

The force and displacement are still

$d=2.2i+cj$ (displacement)

$F=3.2i-3.8 j$ (force)

Therefore, by calculting the scalar product between force and displacement and equating it to the work done (4.0 J), we find:

$W=F\cdot d$

$4.0 =(3.2i-3.8j)\cdot (2.2i+cj)=7.04-3.8c\\3.8c=3.04\\c=\frac{3.04}{3.8}=0.8$

c)

In this problem instead, the work done on the particle is negative:

$W=-1.8 J$

As before, the force and displacement are

$d=2.2i+cj$ (displacement)

$F=3.2i-3.8 j$ (force)

And so again, we calculate the scalar product between force and displacement and we equate it to the work done on the particle, -1.8 J.

Doing so, we find:

$W=F\cdot d$

$-1.8=(3.2i-3.8j)\cdot (2.2i+c)=7.04-3.8c\\3.8c=8.84\\c=\frac{8.84}{3.8}=2.33$

7 0

3 years ago

Plz help with these 5 The backbone is made up of 26 small bones called ___________. What are the characteristics of bones? (list

spin [16.1K]

Answer:

The backbone, spine or vertebral column is made up of 26 small bones called the vertebrae.

The characteristics of bones include:

1. They are strong and rigid

2. They are composed of bone cells called osteocytes.

3. They are lightweight

4. They have a honeycomb-like matrix internally, which helps to give them rigidity.

5. They exist in various types and shapes.

6. They have the ability to grow and repair when damaged

7. They contain inorganic minerals such as calcium and phosphate

The two types of joints are the movable and immovable joints.

Ligaments are bands of tough elastic fibrous tissue around that found around the joints whose function is to link bone to bone, give support to joints as well as limit their movement.

Explanation:

The backbone, spine or vertebral column is made up of 26 small bones called the vertebrae. The 26 small bones include 24 separate vertebrae interspaced with cartilage, and then additionally the sacrum and coccyx. The vertebral column is divided into five regions: cervical, thoracic, lumbar, sacral and coccygeal regions.

A bone is a rigid tissue that is part of the skeleton in vertebrate animals. The characteristics of bones include:

1. They are strong and rigid

2. They are composed of bone cells called osteocytes.

3. They are lightweight

4. They have a honeycomb-like matrix internally, which helps to give them rigidity.

5. They exist in various types and shapes.

6. They have the ability to grow and repair when damaged

7. They contain inorganic minerals such as calcium and phosphate

Joints are the junctions where two bones meet. They serve various functions which include allowing for movement of the body and binding the skeleton together.

The two types of joints are the movable and immovable joints.

Ligaments are bands of tough elastic fibrous tissue around that found around the joints whose function is to link bone to bone, give support to joints as well as limit their movement.

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3 years ago

Gravitational energy can be negative?

AlladinOne [14]

answer:

yes

explanation:

At a separation of the surface of Earth (r=6400km) gravity wants pull the test mass closer and closer. ... So the work done by gravity is NEGATIVE. The gravitational potential energy is negative because us trying to do the opposite of what gravity wants needs positive energy.

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3 years ago

1 Beth isn't a very good student. She's very ......<br>A rude<br>B lazy<br>C clever

kap26 [50]

Answer:

c she's very clever

Explanation:

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3 years ago

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