η = 13.8 lm/W. The luminous efficacy of a incandescent lightbulb that produces 830 lumens and consumed a power of 60 W is 13.8 lm/W.
The luminous efficacy of a light source is the relationship between the luminous flux (in lumens) emitted by a light source and the power (in watts). The luminous efficacy of a light source or luminous efficiency measures the part of electrical energy that is used to illuminate and is obtained by dividing the luminous flux emitted by the electrical power consumed. Luminous efficiency is expressed in lumens per watt (lm / W). It is given by the relation:
η = F / P. Where F is the luminous flux, and P is the power consumed by the light source.
The efficacy of a 60.0 W incandescent lightbulb that produces 830 lm is:
η = 830 lm / 60 W
η = 13.8 lm/W
Answer:
The acceleration at lowest point is 19.62 m/s^2
Explanation:
Conservation of energy is an concept in which it is stated that the energy of an isolated object remains the same. Energy changes from one form to another.
Lets Assume
Constant of string is K
By using the conservation of energy we will have the following equation
1/2 x 80^2 x K = m x 9.81 x 120
3200 K = 1177.2 m
K = 1177.2 m / 3200
K = 0.368 m
At the lowest point we will have
a = ( K x X - m x g ) / m
a = ( 0.368 m x 80 - m x 9.81 ) / m
a = 19.62 m / s^2
So, the acceleration at lowest point is 19.62 m/s^2
The concept used to solve this problem is that given in the kinematic equations of motion. From theory we know that the change in velocities of a body is equivalent to twice the distance traveled by acceleration, in other words:
Where,
Final and initial velocity
a = Acceleration
x = Displacement
For the given case, the displacement is equivalent to the height (x = h) and the acceleration is the same gravitational acceleration (a = g). In turn we do not have initial speed therefore
Our values are given as
Replacing we have that,
Therefore the speed with which the liquid sulfur left the volcano is 529.15m/s
Given:
m(mass of the box)=10 Kg
t(time of impact)=4 sec
u(initial velocity)=0.(as the body is initially at rest).
v(final velocity)=25m/s
Now we know that
v=u+at
Where v is the final velocity
u is the initial velocity
a is the acceleration acting on the body
t is the time of impact
Substituting these values we get
25=0+a x 4
4a=25
a=6.25m/s^2
Now we also know that
F=mxa
F=10 x6.25
F=62.5N
Complete Question
Suppose you hit a steel nail with a 0.500-kg hammer, initially moving at 15.0 m/s and brought to rest in 2.80 mm. How much is the nail compressed if it is 2.50 mm in diameter and 6.00-cm long.What Average force is excreted on the Nail
Answer:
Explanation:
From the question we are told that:
Mass 
Initial Velocity 
Distance 
Diameter 
Length 
Generally the equation for Force is mathematically given by
