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3 years ago

Which type of wave has a frequency just higher than violet visible light and is used by the skin to produce Vitamin D?

1 answer:

4 0

Ultraviolet rays can help us get vitamin D, but they can also damage or skin if w are exposed for too long.

Your answer is D.

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considere que o calor específico de um material presente nas cinzas seja c=0,8j/gc. Supondo que esse material entre na turbina a

drek231 [11]

Answer:

3120J

Explanation:

Given parameters:

C = Specific heat capacity = 0.8J/g°C

Initial temperature = 20°C

Mass given = 5g

Final temperature = 800°C

Unknown:

Energy given to the mass = ?

Solution:

To find the energy given to the mass, let us simply use the expression below:

H = m c ΔT

H is the unknown, the energy supplied

m is the mass of the substance

c is the specific heat capacity

ΔT is the change in temperature

Input the variables;

H = 5 x 0.8 x (800 - 20) = 3120J

7 0

3 years ago

If the mass of the spacecraft were doubled, how much would the force of gravity would change?

vodka [1.7K]

F=mg
if m doubled, F would double as well

5 0

3 years ago

Which factors affect friction between two solid surfaces?

a_sh-v [17]

1) newton of the surfaces in contact (the smoothness of the surfaces)

2) how hard the surfaces press together

6 0

3 years ago

Read 2 more answers

A 7 kg ball is moving at a constant speed of 5 m/s. A force of 300 N is applied to the ball for 4 s. The new speed of the ball i

olasank [31]

Answer:

The new speed of the ball is 176.43 m/s

Explanation:

Given;

mass of the ball, m = 7 kg

initial speed of the ball, u = 5 m/s

applied force, F = 300 N

time of force action on the ball, t = 4 s

Apply Newton's second law of motion;

$F = ma = \frac{m(v-u)}{t}\\\\m(v-u) = Ft\\\\v-u = \frac{Ft}{m}\\\\v = \frac{Ft}{m} + u$

where;

v is new speed of the ball

$v = \frac{Ft}{m} + u\\\\v =\frac{300*4}{7} + 5\\\\v = 176.43 \ m/s$

Therefore, the new speed of the ball is 176.43 m/s

8 0

3 years ago

What is the average speed of a cheetah that runs 88 m in 5 seconds

vovangra [49]

So, the average speed of the Cheetah is 17.6 m/s.

<h3>Introduction</h3>

Hello ! I'm Deva from Brainly Indonesia. This time, I will help regarding the average speed. The average speed is obtained from finding the average of the speeds that occur or can be detected from the division between distance and travel time. The average speed can be formulated by :

$\boxed{\sf{\bold{\overline{v} = \frac{s}{t}}}}$