Work Energy

Question 1

If there is external forces, (so much energy not conserved), what’s the equation?

Answer 1

Ke 1 + gph1 +- work done = ke 2 + gpe2

Question 2

What to take care not to accidentally do considering weight force and gpe in work energy

Answer 2

Don’t do gpe twice, the force done by weight is counted in gpe

Question 3

Yh NEVER TAKE HORIXONTAL COMPMOF WEIGHT AS WORK DONE WHEN YOU ALREADY DID GPE LOL

Question 4

Tension csn do work too!

Question 5

With power = fv, as v increases what happens to f and thus acceleration and thus where do you find maximum speed

Answer 5

As v increases, f decreases for constant poeer
If f decreases, a devreases for constant mass

The max v is thus achieved when a is 0, so use resistive forced etc to find force when a =0

Question 6

When power and velocity is used, WHY CANT WE USE SUVATS?

Answer 6

This because we just saw acceleration changes as velocity increases, so constant acceleration means no

Question 7

Power for velocity / power for work energy?

Answer 7

For velocities, all need to know is thst max velocity occurs when a is 0 so resuktsnt force is 0

And fore energy remember p = work done / time, use equation to find how much energy put in