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3 years ago

Renewable resources need to be conserved because

Physics

1 answer:

creativ13 [48]3 years ago

4 0

Answer:

(A) We are using them faster than they are replenished by nature

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What part of the electromagnetic spectrum can be seen by humans

Amanda [17]

Answer:

Visible light

Explanation:

Electromagnetic spectrum is the classification of the electromagnetic waves according to their frequency/wavelength. In order from the shortest to the longest wavelength, we have

Gamma rays

X-rays

Ultraviolet

Visible light

Infrared

Microwaves

Radio waves

All these waves are invisible to human eye, except for the part referred as 'visible light'. The electromagnetic waves of this part of the spectrum are visible to human eye, and they appear as a different color depending on their wavelength. In particular, we have:

Violet: 380-450 nm

Blue: 450-495 nm

Green: 495-570 nm

Yellow: 570-590 nm

Orange: 590-620 nm

Red: 620-750 nm

4 0

2 years ago

A high-jump athlete leaves the ground, lifting her center of mass 1.8 m and crossing the bar with a horizontal velocity of 1.4 m

Romashka [77]

Answer:

The minimum speed when she leave the ground is 6.10 m/s.

Explanation:

Given that,

Horizontal velocity = 1.4 m/s

Height = 1.8 m

We need to calculate the minimum speed must she leave the ground

Using conservation of energy

$K.E+P.E=P.E+K.E$

$\dfrac{1}{2}mv_{1}^2+0=mgh+\dfrac{1}{2}mv_{2}^2$

$\dfrac{v_{1}^2}{2}=gh+\dfrac{v_{2}^2}{2}$

Put the value into the formula

$\dfrac{v_{1}^2}{2}=9.8\times1.8+\dfrac{(1.4)^2}{2}$

$\dfrac{v_{1}^2}{2}=18.62$

$v_{1}=\sqrt{2\times18.62}$

$v_{1}=6.10\ m/s$

Hence, The minimum speed when she leave the ground is 6.10 m/s.

6 0

3 years ago

A large man sits on a four-legged chair with his feet off the floor. The combined mass of the man and chair is 95.0 kg. If the c

Leto [7]

Answer:

Pressure, $P=29.6\times 10^5\ Pa$

Explanation:

It is given that,

Combined mass of the man and the chair, m = 95 kg

Radius of the leg of chair, r = 0.5 cm = 0.005 m

A large man sits on a four-legged chair with his feet off the floor. The force acting per unit area is called the pressure exerted.

$P=\dfrac{F}{A}$

$P=\dfrac{mg}{A}$

Area of 4 legs, A = 4 A

$P=\dfrac{mg}{4\pi r^2}$

$P=\dfrac{95\times 9.8}{4\pi (0.005)^2}$

$P=29.6\times 10^5\ Pa$

So, the pressure each leg exert on the floor is $29.6\times 10^5\ Pa$ . Hence, this is the required solution.

7 0

3 years ago

An electric circuit consists of a variable resistor connected to a source of constant potential difference. If the resistance of

yulyashka [42]

Then nothing will happen

5 0

2 years ago

A pendulum can be formed by tying a small object, like a tennis ball, to a string, and then connecting the other end of the stri

Usimov [2.4K]

Answer:

1- t^3

2- t^2

3- t1

Explanation:

The acceleration produced in a body, while travelling in a circular motion, due to change in direction of motion is called centripetal acceleration. The formula of the centripetal acceleration is as follows:

ac = v²/r

where,

ac = centripetal acceleration

v = speed

r = radius

for a constant radius the centripetal acceleration will be directly proportional to the speed of object. The speed of pendulum will be lowest at t1 due to zero speed initially. Then the speed will increase gradually having greater speed at t^2 and the highest speed and centripetal acceleration at t^3. Therefore, the three instants in tie can be written in following order from greatest centripetal acceleration to lowest:

1- t^3

2- t^2

3- t1

5 0

2 years ago