Askier is skiing down a slope on the mountain. is the mechanical energy conserved? why or why not?

Explanation:

Mechanical energy is the sum of the kinetic energy and the potential energy of the system.

According to the law of conservation of the mechanical energy, the total amount of the mechanical energy is constant in the closed system.

A skier is skiing down a slope on the mountain. A skier possess the potential energy due to the height on the mountain. The potential energy of a skier starts decreasing while coming down.

The kinetic energy of a skier starts increasing while coming down from the mountain. It is due to motion of a skier.

But the mechanical energy of the system is not conserved in this case as the some energy is lost due to the friction. A skier meets an unpacked snow which decreases the speed. There is dissipation of energy due to friction.

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27