At the maximum height of a projectile’s trajectory—
a) velocity is 0
b) potential energy is 0
c)dot product of velocity & acceleration is 0
d)cross product of velocity & acceleration is 0

which one of the above is correct?

D. Cross product of velocity & amp; acceleration is 0

Well, a, c, and d are all true, but the simple reason is that the velocity is zero at the top of the flight. The best, simplest answer is 'a'.

ι вєℓιєνє ιт ιѕ тнє fιяѕт ¢нσι¢є(α.)

нє ѕнσυℓ∂ ѕмιℓє ρσℓιтℓу αи∂ ѕρєαк тσ тнє ρєяѕσи ωнσ ιѕ ιитєяяυριиg αfтєя тнє ∂ιѕ¢υѕѕισи

нσρє ι ¢συℓ∂ нєℓρ.