Question

If 2.0 J of work is done in raising a 180g apple, how far is it lifted?

Answer 1

1.14 meters

Explanation:

You have already learned that work and energy have same units i.e. Joule (J).

If the object has travelled some distance (upwards) then there must be some potential difference (increased potential energy).

Thus the energy needed to lift the ball can be found by this formula:

`E_p` = `m*g*h`

Where `E_p` means potential energy needed (or simply work done). m stands for mass, g for gravitational energy, and h for the height reached.

Now we know the energy(2 J), the mass (0.18 kg), and gravitational energy (9.8 m/s^2). Putting into the formula we get:

`2 = 0.18 * 9.8 * h`

`2/(0.18*9.8)=h`

`2/1.76=h`

`1.14=h`

Finally,

height reached above the ground = 1.14 m