Could you please explain to me these problems, I don't understand them.
Do 100 J of work in 50 s and your power output is?
- I got 2, but not sure of the units.
A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of ?
I don't understand this queston
A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of?
I don't understand this question
a Joule/second is defined as a watt.
The second is conservation of energy. The arrow should have the same KE as the bow had PE.
The third is exactly the same, The diver had mgh of PE, he should have that KE at the bottom.
Sure, I'll be happy to explain these problems to you.
Let's start with the first problem:
"Do 100 J of work in 50 s and your power output is?"
To find the power output, we need the formula:
Power (P) = Work (W) / Time (t)
In this case, the work done is given as 100 J and the time taken is 50 s. Plugging these values into the formula, we have:
P = 100 J / 50 s
Simplifying the equation, we get:
P = 2 J/s
So, the power output is indeed 2, but the units should be in joules per second (J/s).
Moving on to the second problem:
"A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of?"
In this problem, we are dealing with potential and kinetic energy. Potential energy (PE) is the energy an object has due to its position or condition, while kinetic energy (KE) is the energy an object possesses due to its motion.
The question states that the bow has 40 J of potential energy. When the arrow is fired, that potential energy is converted into kinetic energy. Therefore, the kinetic energy of the arrow will ideally be equal to the potential energy of the bow, which is 40 J in this case.
Lastly, let's address the third problem:
"A diver who weighs 500 N steps off a diving board that is 10 m above the water. The diver hits the water with kinetic energy of?"
Here, we need to use the concept of gravitational potential energy and convert it into kinetic energy. The formula for gravitational potential energy (PE) is given as:
PE = weight (W) x height (h)
The weight of the diver is 500 N, and the height is 10 m. Plugging these values into the formula, we have:
PE = 500 N x 10 m
Simplifying the equation, we get:
PE = 5000 J
Since the potential energy is converted completely into kinetic energy as the diver hits the water, the kinetic energy will be the same as the potential energy, which is 5000 J.