A man walking east at 1 mi/h on a moving sidewalk which is moving east at 12 mi/h. What is the mans velocity as observed by a lady standing next to the moving sidewalk? 3 mi/h east
1 mi/h west
1 mi/h east
3 mi/h west

answer: the potential energy decreases from 379 j to 243 j

explanation:

for the law of conservation of energy, the total energy in a system must be conserved. the total energy of the system is given by the sum of kinetic (k) and potential (u) energy:

e = k + u

the total energy is e=675 j, and this does not change.

initially, the kinetic energy is k=296 j, so the potential energy is

at the end, the kinetic energy is k=432 j, so the potential energy is

so, we see that the potential energy has decreased from 379 j to 243 j.

1. 5

2.0.216

3.when you turn a screw,it undergoes two kinds of motion at the same time. ▶translatory motion or linear motion - motion in a straight line ..and, ▶circular motion - motion around an axis ( because screw is turned also around an axis and it goes inside through a straight path).

explanation: