If it produces 20J of light energy in a second, then that 20J is the 10% of the supply that becomes useful output.
20 J/s = 10% of Supply
20 J/s = (0.1) x (Supply)
Divide each side by 0.1:
Supply = (20 J/s) / (0.1)
<em>Supply = 200 J/s </em>(200 watts)
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Here's something to think about: What could you do to make the lamp more efficient ? Answer: Use it for a heater !
If you use it for a heater, then the HEAT is the 'useful' part, and the light is the part that you really don't care about. Suddenly ... bada-boom ... the lamp is 90% efficient !
Answer:
14 seconds
Explanation:
Distance covered by sports car is measured with 21*t where t is time.
Distance covered by police is measured with at^2/2(t-time, a-acceleration) as it doesnt have starting velocity. If the distances are equal(police catches sport car)
then we have 21t=3/2*t^2 Solving this equation we get t=14 & t=0;
excluding the starting point we have 14 seconds
Answer:
b -algae
Explanation:
The most common producers in aquatic ecosystems are the algae. They are called phytoplanktons.
- In the food web and food chain of aquatic ecosystems, they usually set out with the algae.
- These algae are called phytoplanktons.
- They are the producers in all aquatic ecosystem.
- Phytoplanktons consists of algae and cyanobacteria.
- Just like plants on land, phytoplanktons manufacture food in an aquatic ecosystem.
Answer:
the diver's speed is independent of the launch height.
Explanation:
For this exercise we must use Newton's second law
fr - W = m a
the friction force has the general form
fr = b v
Let's analyze this equation to find out what happens with the speed of the distant club.
When jumping, the initial speed is zero, so the friction force is zero and has an acceleration equal to the acceleration of gravity, as the speed increases the friction force increases decreasing the acceleration until it becomes zero, when it arrives at this value the velocity it has is called terminal velocity and this velocity remains fixed in relation to the trajectory.
fr = W
v = cte
The distance or time in which this equilibrium is reached is relatively fast, so the diver's speed is independent of the launch height.
