A crate is lifted vertically 1.5 m and then held at rest. The crate has weight 100 N (i. e., it is supported by an upward force of 100 N). How much work was done in lifting the crate from the ground to its final position? 1. 150 J 2. More than 150 J 3. None of these 4. A bit less than 150 J 5. No work was doneNow suppose the crate is lifted so rapidly that air resistance was significant during the raising. How much work was done by the lifting force as the box was raised 1.5 m?1. None of these 2. No work was done. 3. More than 150 J 4. Still 150 J 5. A bit less than 150 J because the air partially supported the crate.

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

A2.00-m long piano wire with a mass per unit length of 12.0 g/m is under a tension of 8.00 kn. what is the frequency of the fundamental mode of vibration of this wire?

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.