Question

the object at point a has a potential energy of 420 j and a total energy of 560 j. what is the kinetic energy?
height (m) vs. time (s)
options: 980 j, 140 j, 560 j

Explanation:

Step1: Recall the total energy formula

The total mechanical energy \( E_{total} \) is the sum of potential energy \( E_p \) and kinetic energy \( E_k \), so \( E_{total}=E_p + E_k \).

Step2: Rearrange the formula to solve for \( E_k \)

We can rearrange the formula to \( E_k = E_{total}-E_p \).

Step3: Substitute the given values

Given \( E_{total} = 560\space J \) and \( E_p = 420\space J \), substitute into the formula: \( E_k=560 - 420 \).

Step4: Calculate the result

\( 560-420 = 140\space J \).

Answer:

140 J (corresponding to the option: 140 J)