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defon
4 years ago
13

Dinosaurs emerged during what time period

Physics
1 answer:
swat324 years ago
6 0
Dinosaurs lived between 230 and 65 million years ago, in a time known as the Mesozoic Era<span>. This was many millions of years before the first modern humans, Homo sapiens, appeared. </span>
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When an electron de-excites from the third quantum level to the second, and then to the ground state, two photons are emitted. T
Leokris [45]

Answer:

ground state

Explanation:

  Lets take  

n=3 ,n=2 ,n=1 are the energy level.

Energy level n=1 is the ground energy level.

The energy from 3 to 1 = hν

The energy from 3 to 2 = hν₁

The energy from 2 to 1 = hν₂

We can say that

hν = hν₁ +  hν₂

If the electron were de-excitation from the third level to ground level then the sum of emitted frequency will be equal to the frequency of a single electron.

Therefore the answer is ground state.

3 0
3 years ago
Distinguish between basic and derived units
alex41 [277]

Answer:

Base units are defined units based on specific objects or events in the physical world. Derived units are defined by combining base units.

Base units are defined by a particular process of measuring a base quantity whereas derived units are defined as algebraic combinations of base units. For example, length is a base quantity in both SI and the English system, but the meter is a base unit in the SI system only.

8 0
3 years ago
A force platform is a tool used to analyze the performance of athletes measuring the vertical force that the athlete exerts on t
Phoenix [80]

Answer:

a.I=981.34 N*s

b.v_f=3.96 m/s

c.v_{f1}=3.63m/s

d.y_f=0.673m

Explanation:

Given: m=67kg, h=0.720m, 0

a.

I=\int\limits^{t_1}_{t_2} {F(t)} \, dt

F(t)=9200*t-11500t^2

I=\int\limits^{0.8s}_{0s}{9200*t-11500*t^2} \, dt

I=4600*t^2-3833.3*t^3|(0.80,0)

I=2944-1962.66=981.35

I=981.34 N*s

b.

v_f^2=v_i^2+a*y'

Starting from the rest

v_f^2=0+2*9.8m/s^2*0.80s

v_f^2=15.68

v_f=\sqrt{15.68m^2/s^2}=3.96 m/s

c.

I_{total}=p_f

I_1-m*g*d=m*v_{f1}-m*v_f

981.34-67kg*9.8m/s^2*0.720=67.0kg*v_{f1}-67.0kg*(-3.96m/s)

Solve to vf

v_{f1}=3.63m/s

d.

v_f^2=v_i^2+2*a*y_f'

y_f'=v_i/2*a =(3.63m/s)^2/2*9.8m/s^2

y_f=0.673m

7 0
3 years ago
Which situation describes a system with decreasing gravitational potential energy?
umka2103 [35]
An example of a system with decreasing gravitational potential energy is a ball in free fall. 

At its initial height h, the ball has a gravitational potential energy equal to
U=mgh
where m is the ball mass and g is the gravitational acceleration. As the ball falls toward the ground, its height h decreases, and so its gravitational potential energy decreases as well, according to the formula 
U=mgh'
where h' is the new height of the ball.
8 0
3 years ago
A runner has a temperature of 40°c and is giving off heat at the rate of 50cal/s (a) What is the rate of heat loss in watts? (b)
Andrew [12]

Answer:

(a)  209 Watt

(b) 4482.8 seconds

Explanation:

(a) P = 50×4.18

Where P = rate of heat loss in watt

    P = 209 Watt

Applying,

Q = cm(t₁-t₂)................ Equation 1

Where Q = amount of heat given off, c = specific heat capacity capacity of human, m = mass of the person, t₁ and t₂ = initial and final temperature.

From the question,

Given: m = 90 kg, t₁ = 40°C, t₂ = 37°C

Constant: c = 3470 J/kg.K

Substtut these values into equation 1

Q = 90×3470(40-37)

Q = 936900 J

But,

P = Q/t.............. Equation 2

Where t = time

t = Q/P............ Equation 3

Given: P = 209 Watt, Q = 936900

Substitute into equation 3

t = 936900/209

t = 4482.8 seconds

5 0
3 years ago
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