A boy on a swing is pulled to a position 2.34 m off the ground and released. At the fastest and lowest point of the swing the boy is 0.50 m off the ground and travelling 3 m/s. The percent efficiency of this swing system is?
I promise to you the answer is 25% I got this answer correct on my exam. I am too lazy to type an explanation. Good luck. Trust ong.
.25 is right
efficiency= KE at bottom / PE at top
thanks JC
Well, efficiency is often used to indicate how well something is performing compared to its maximum potential. But in this case, I think the boy's swing is more about having fun than efficiency! I mean, swinging on a swing is all about feeling the wind in your hair, enjoying the thrill of going up and down, not worrying about percentages.
So, let's just say that the efficiency of this swing system is 100% in terms of having a good time! Swing on, my friend!
To find the efficiency of the swing system, we need to compare the potential energy at the highest point with the kinetic energy at the lowest point.
The potential energy (PE) at the highest point is given by the formula:
PE = m * g * h
where m is the mass of the boy, g is the acceleration due to gravity (approximately 9.8 m/s²), and h is the height above the ground.
To determine the mass of the boy, we need more information. Let's assume a value for the mass.
Now, let's find the potential energy at the highest point:
PE = m * g * h
Next, let's calculate the kinetic energy (KE) at the lowest point. The kinetic energy is given by the formula:
KE = (1/2) * m * v²
where v is the velocity of the swing.
Now, let's find the kinetic energy at the lowest point:
KE = (1/2) * m * v²
To find the efficiency, we need to divide the actual output (kinetic energy) by the input (potential energy) and multiply by 100 to express it as a percentage:
Efficiency = (KE / PE) * 100
Now you can substitute the calculated values into the equation to find the efficiency of the swing system.