A book with a mass of 3.3 kg sits on a bookshelf. If it has a gravitational
potential energy of 57 J, how high is the shelf? The acceleration of gravity is
9.8 m/s2

Classify each possible hypothesis about a medicinal aloe vera plant as falsifiable or non-falsifiable. aloe vera gel is the best natural skin moisturizer. aloe vera gel can heal wounds by boosting cell renewal. aloe vera juice tastes better than carrot juice. drinking aloe juice can reduce the risk of lung cancer.

Explain why electric current cannot exist if a current doesn't have a voltage source.

Often called simply "velocity," this is the velocity of an object at a particular moment in time.