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inysia [295]
2 years ago
5

The total power input to the LED was 0.24 W.

Physics
1 answer:
just olya [345]2 years ago
4 0

Answer: How do you calculate useful power output?

Explanation:  Hence, useful energy output:

Wuseful=F×d=10×5=50 J W useful = F × d = 10 × 5 = 50 J. ...

Ewasted=65−50=15 J E wasted = 65 − 50 = 15 J. ...

Efficiency=Useful energy outputTotal energy input×100%=5065×100%=76.9% Efficiency = Useful energy output Total energy input × 100 % = 50 65 × 100 % = 76.9 %

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The alarm at a fire station rings and a 87.5-kg fireman, starting from rest, slides down a pole to the floor below (a distance o
blsea [12.9K]

Answer:

F_f=840N

Explanation:

From the question we are told that

Weight of fireman W_f= 87.5kg

Pole distance D=4.10m

Final speed is V_f 1.75m/s

Generally the equation for velocity is mathematically represented as

v^2 = v_0^2 + 2 a d

Therefore Acceleration a

a'= v^2 / 2 d

a'= 0.21m/s^2

Generally the equation for Frictional force F_f is mathematically given as

F_f=m*a

F_f=m*(g-0.21)

F_f=87.5*(9.81-0.21)

Therefore

F_f=840N

6 0
3 years ago
Which of the following elements are least abundant in the solar system?
Art [367]
The answer to this question is Helium
7 0
2 years ago
A stone is thrown with an initial speed of 11.5 m/s at an angle of 50.0 above the horizontal from the top of a 30.0-m-tall build
rewona [7]

Answer:

The magnitude of the horizontal displacement of the rock is 7.39 m/s.

Explanation:

Given that,

Initial speed = 11.5 m/s

Angle = 50.0

Height = 30.0 m

We need to calculate the horizontal displacement of the rock

Using formula of horizontal component

v_{x}=u\cos\theta

Put the value into the formula

v_{x}=11.5\times\cos50

v_{x}=7.39\ m/s

Hence, The magnitude of the horizontal displacement of the rock is 7.39 m/s.

8 0
3 years ago
A ball of mass m falls vertically, hits the floor with a speed ui , and rebounds with a speed u f . what is the magnitude of the
Sholpan [36]

Answer:

Change of momentum = M (Vf - (-Vi))   where V represents the scalar speeds of the ball or

I = M (ui + uf)  and I is the impulse ΔM V = I     Force = Change in Momentum

5 0
1 year ago
When beryllium-7 ions (m = 11.65 × 10-27 kg) pass through a mass spectrometer, a uniform magnetic field of 0.205 T curves their
AysviL [449]

Answer:

ratio =0.3075 T

Explanation:

The magnetic field B creates a force on a moving charge such that

F = qvB

Now this causes a centripetal acceleration

F =  = mv^2/r

 so

qvB = mv^2/r ...........(i)

B = mv/(rq)  ...............(ii)

If  accelerating potential V is  same and  then  kinetic energy equals the potential energy difference

\frac{1}{2} mv^2 = Vq

v = \sqrt{(2Vq/m)}      put these value in equation (ii)

B = m\frac{\sqrt{(2Vq/m)} }{rq}  

simplifying we get  

B =m \frac{(\sqrt{ 2Vm/q})}{r}

for same location r will be same in both case

B_{7} = \frac{ \sqrt{(m_{7})(2V/q) }}{r}      ..............(iii)

B_{10} = \frac{ \sqrt{(m_{10})(2V/q) }}{r}    ..........(iv)

 dividing (iv) and (iii) equation we get

\frac{B_{10}}{B_{7}}   =   \sqrt{\frac{m_{10}}{{m_7}} }

{B_{10}}  =  B_{7}  \sqrt{\frac{m_{10}}{{m_7}} }

B_{10}       = 0.2574T\sqrt{\frac{  (1.663x10^-26}{(1.165x10^-26)}

so on solving we get  

             =0.3075 T

5 0
3 years ago
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