4. Energy concepts

Question 1

Here’s the problem, deriving the equation. Additionally, this one’s actually one of the harder topics in this unit too due to quantity.

Answer 1

D:

Question 2

Work done = force x distance
or (in addition to angles)
W = Fcosθ x X

Reveal answer

Answer 2

okay?

GIVEN IN DATA BOOKLET, U JUST NEED TO ACKNOWLEDGE IT

Question 3

1 joule = kgm^2s^-2

Answer 3

Errr okay?

Question 4

Work done = energy
Tho take GPE in consideration

Answer 4

Wat

Question 5

Equation for kinetic energy?
(given in data booklet)
and what to expect here?

Answer 5

Ek = 1/2 mv²

• Re-arranging for certain values
• Maybe there’s more

Question 6

Equation for gravitational potential energy?
(in data booklet just not the same here)

Answer 6

GPE = m x g x h

Question 7

How to find work done in them slide questions?
(also still in the data booklet)

Answer 7

Fx = 1/2mv² - 1/2mu²

Question 8

How to find average resistive force in them typical type shi questions?
What to expect from these?

Answer 8

1. Gain GPE
2. Gain kinetic energy
3. GPE = Ek + wd against friction
4. Re-arrange for that wd
5. 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

Question 9

Define elastic potential energy and 1 additional thing?

Answer 9

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

Question 10

How to find EPE in a spring?

Answer 10

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

Question 11

For sure u can explain energy changes in different parts of a journey

Answer 11

• Talk bout Kinetic
• Talk bout potential
• Talk about energy loss

Question 12

Define power?

Answer 12

The rate of doing work

That’s why it’s Js^-1 O_o

Question 13

Equation for power?
(in the data booklet)

Answer 13

P = w/t

Question 14

The alternate really good way for finding power?

Answer 14

P = Fv
W = N x ms^-1

• Might be a chance to show how it homogenous, which idk how to do :

Question 15

How to find efficiency?

Answer 15

% efficiency = useful energy output/total energy input x all by 100

Question 16

Oh ye think about loss of energy during certain movements

Answer 16

• Friction
• Sound
• Heat
• Ye.

Question 17

Show unit expressed in SI units

Answer 17

W = Js^-1
= kgm^2s^-3

Question 18

Yikers

Answer 18

O_o

Question 19

Use the past paper questions n stuff

Answer 19

Makes sense

Question 20

State the principle of conservation of energy

Answer 20

Energy cannot be created or destroyed but only transferred from 1 form to another of 1 place to another