Answer:
1. W = 8848 J
2. W = 7848 J
3. W = 6848 J
Explanation:
The work (W) can be found using the following equation:
[tex] W = E_{k} + E_{p} [/tex]
Where: E(k) is the kinetic energy and E(p) is the potential energy
Now let's find the work for every stage.
Stage 1:
[tex] W = E_{k} + E_{p} = \frac{1}{2}mv^{2} + mgh [/tex]
Where: m is the mass, g is the gravity, h is the height, v is the speed
[tex] W = \frac{1}{2}mv^{2} + mgh = \frac{1}{2}80 kg*(5 m/s)^{2} + 80 kg*9.81 m/s^{2}*10 m = 8848 J [/tex]
Stage 2:
[tex] W = E_{k} + E_{p} = 0 + E_{p} [/tex]
The kinetic energy is equal to zero because the acceleration is constant.
[tex] W = E_{p} = mgh = 80 kg*9.81 m/s^{2}*10 m = 7848 J [/tex]
Stage 3:
[tex] W = E_{k} + E_{p} = \frac{1}{2}mv^{2} + mgh = -\frac{1}{2}80 kg*(5 m/s)^{2} + 80 kg*9.81 m/s^{2}*10 m = 6848 J [/tex]
I hope it helps you!
