Question

4. With respect to a mass of 1kg. (a) How much change in elevation must it undergo to change its potential energy by 1 kJ? (g=9.8 ms²) ​

Answer 1

Answer:

102 m upwards.

Explanation:

Just from a qualitative analysis we can tell the mass it needs to go upwards. How much we determine with the fact that the increase will be - in absolute value - equal to the work gravity does on it to go down that same distance.

Fixed that work being 1 kJ, we get

$\vec F \cdot \vec{ \Delta h} = |F| |\Delta h| cos 0 = ( 9.8 N )\Delta h \cdot 1 = 10^3 J\\\Delta h = \frac {10^3}{9,8} m \approx 102 m$