Question

When the 9-kg box reaches point a it has a speedva = 13 m/s ?

Answer 1

Explanation:

we know, power = V²/R

Here , V is the potential difference

And R is the resistance of wire.

Given,

Resistance of wire per unit length = 2 Ω/m

Let length of wire is L

Then, resistance of wire = resistance of wire per unit length × length of wire

= 2L Ω

Power = 1kW = 1000 watt

Potential difference , V = 200V

∴ 1000 = (200)²/2L

1000 = 40000/2L

L = 20 m

Hence, length of wire is 20m