Question

this model shows a ball being shot from the cannon. which of these statements accurately describes the energy of the cannonball? select all that apply.
a the kinetic energy is lowest at point e.
b the potential energy is lowest at point e.
c the kinetic energy is greatest at point c.
d the potential energy is greatest at point c.

Explanation:

Step1: Analyze potential energy

Potential energy \(U = mgh\) (where \(m\) is mass, \(g\) is acceleration due to gravity, \(h\) is height). At point \(C\), height \(h\) is maximum. So potential energy is greatest at \(C\). At point \(E\), height \(h\) is minimum. So potential energy is lowest at \(E\).

Step2: Analyze kinetic energy

Kinetic energy \(K=\frac{1}{2}mv^{2}\). At the highest point \(C\), vertical component of velocity is \(0\), but there is horizontal velocity. At point \(E\), if we assume no air - resistance, by conservation of mechanical energy \(E = K+U\). Since \(U\) is minimum at \(E\), \(K\) is relatively large at \(E\) (not lowest). The kinetic energy is not greatest at \(C\) (because vertical velocity is \(0\) at \(C\) for projectile motion at the highest point, and total speed is less than at \(A\) or \(E\) if no air - resistance).

Answer:

B. The potential energy is lowest at point \(E\); D. The potential energy is greatest at point \(C\)