1. A book resting on a shelf was found to have a gravitational potential energy
of 12 J relative to the ground. If the
book falls to the ground, neglecting air
resistance, what is the kinetic energy of
the book just as it was about to hit the
ground?

12J

Explanation:

Right before it hits the ground, the initial potential energy and the final kinetic energy will equal each other due to conservation of energy.

i don't understand. explain it clearly

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft