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3 years ago

Explain why people have different skin colors?

Physics

1 answer:

stiks02 [169]3 years ago

5 0

I think it because of UV rays ultra violet ray which can make their colors different

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A radio has 100J of energy transferred by electricity. 20J are transferred by heating and 10J are transferred by sound. How many

seraphim [82]

Answer:

70 Joules

Explanation:

3 0

4 years ago

"If the object has a speed of" -2.5 m/s at x = 0m, find its speed at x = 5.00 m and its speed at x = 15.0 m.

frez [133]

Answer:

Hello your question has some missing parts attached below is the missing part

A object of mass 3.00 kg is subject to a force Fx that varies with position as in the figure below.

answer : speed at x = 5 m = 3.35 m/s

speed at x = 15m = 5.12 m/s

Explanation:

initial speed( x = 0 ) = 2.5 m/s

speed at x = 5.00 m = ?

speed at x = 15 m = ?

Determine speed at x = 5 m

First we will apply the expression for work-energy theorem

w = $\frac{1}{2} m(v^2 - v_{0}^2 )$ ----- ( 1 )

where : w = 7.50J, $v_{0}$ = 2.5m/s , m = 3.0 kg ( in the expression of work )

input values into equation 1

7.50 = 1/2 (3 ) ( v^2 - 2.5^2 )

7.50 = 3/2 ( v^2 - 6.25 )

5 j/kg = v^2 - 6.25

∴ v = √11.25 = 3.35 m/s

Determine speed at X = 15

first we will determine the work done form x = 5 to x = 15

W = 7.5J + 15J + 7.5J = 30J, $v_{0}$ = 2.5m/s , m = 3.0 kg

w = $\frac{1}{2} m(v^2 - v_{0}^2 )$ --- ( 2 )

equation2 becomes

30J = 1/2 ( 3 ) ( v^2 - 6.25 )

30J = 3/2 ( V^2 - 6.25 )

20 J/kg = v^2 - 6.25

v = √26.25 = 5.12 m/s

5 0

3 years ago

Physics how to calculate disintegration energy

dimulka [17.4K]

1. The problem statement, all variables and given/known data (a) Calculate the disintegration energy when 232/92U decays by alpha emission into 228/90Th. Atomic masses of 232/92U and 228/90Th are 232.037156u and 228.028741u, respectively. (b) For the 232/92U decay in part (a), how much of the disintegration energy will be carried off by the alpha particle? Given: Mass of 4/2He = 4.002603u c^2 = 931.5MeV

2. Relevant equations E=mc^2

3. The attempt at a solution Well for part (a), first I found the difference in the starting masses and the end masses ie, 232.037156u - (228.028741u + 4.002603u) = 0.005812u I then put this into the equation and got 5.413878MeV. I thought this was right until I read part (b) and now I'm starting to think this might be how I'm meant to do that part, not part (a). Could anyone tell me if I'm even on the right track with this question or should I be using different equations?

4 0

4 years ago

What happens when you add heat to an object and when you cool an object

Katena32 [7]

When you heat up an object three things could possibly happen:

i) Increase in temperature of the object. Imagine heating up water, the temperature increases.

ii) Linear Expansion: The object could increase in length. For example if you heat up a steel rod, the length would increase as a result of linear expansion.

iii) Change of State: The object could change from solid state to liquid state or from liquid state to gaseous state, as the case may be. For example heating ice block to liquid water.

7 0

3 years ago

A particle moves along the x-axis so that its velocity at anytime is t greater than or equal to 0 is given by v(t)=1-sin(2pi t)

UkoKoshka [18]

A) We differentiate the expression for velocity to obtain an expression for acceleration:
v(t) = 1 - sin(2πt)
dv/dt = -2πcos(2πt)
a = -2πcos(2πt)

b) Any value of t can be plugged in as long as it is greater than or equal to 0.

c) we integrate the expression of velocity to find an expression for displacement:
∫v(t) dt = ∫ 1 - sin(2πt) dt
x(t) = t + cos(2πt)/2π + c
x(0) = 0
0 = = + cos(0)/2π + c
c = -1/2π
x(t) = t + cos(2πt)/2π -1/2π

5 0

4 years ago