P 4. Energy Concepts Flashcards
Here’s the problem, deriving the equation. Additionally, this one’s actually one of the harder topics in this unit too due to quantity.
D:
Work done = force x distance
or (in addition to angles)
W = Fcosθ x X
Reveal answer
okay?
GIVEN IN DATA BOOKLET, U JUST NEED TO ACKNOWLEDGE IT
1 joule = kgm^2s^-2
Errr okay?
Work done = energy
Tho take GPE in consideration
Wat
Equation for kinetic energy?
(given in data booklet)
and what to expect here?
Ek = 1/2 mv²
- Re-arranging for certain values
- Maybe there’s more
Equation for gravitational potential energy?
(in data booklet just not the same here)
GPE = m x g x h
How to find work done in them slide questions?
(also still in the data booklet)
Fx = 1/2mv² - 1/2mu²
How to find average resistive force in them typical type shi questions?
What to expect from these?
- Gain GPE
- Gain kinetic energy
- GPE = Ek + wd against friction
- Re-arrange for that wd
- Use W=fd, re-arrange then find that force
F = w/d
- Generally u get asked these from roller coaster/slide type shi
- I recommend to generalise urself with this, could be nice free marks
Define elastic potential energy and 1 additional thing?
Energy possessed by an object when it has been deformed due to force acting on it
In addition, it can become as it was before, can return from deformation
How to find EPE in a spring?
Problemo:
we have:
1/2 Fx
or
1/2 kx²
Partly figured it out:
1/2 Fx is nly for EPE stored in wire
&
1/2 kx2 is for when u try to find the EPE in a graph:
- Gradient of graph = rise/run = F/x = K
- Re-arranging -> F = kx
- OHH THEN SUB EPE EQUATION IN THIS:
1/2 (kx)x = 1/2 kx2
For sure u can explain energy changes in different parts of a journey
- Talk bout Kinetic
- Talk bout potential
- Talk about energy loss
Define power?
The rate of doing work
That’s why it’s Js^-1 O_o
Equation for power?
(in the data booklet)
P = w/t
The alternate really good way for finding power?
P = Fv
W = N x ms-1
- Might be a chance to show how it homogenous, which idk how to do :
How to find efficiency?
% efficiency = useful energy output/total energy input x all by 100