**Equations and Formulae**

Starter

v = u + at

Find the value of v if:

(a) u = 3, a = 5, t = 2

(b) u = -4, a = 2, t = 10

(c) u = -5, a = 0.5, t = -8

Example

A plumber uses the formula C = 25h + 30 to work out how much to charge customers, based on the number of hours she works.

(a) The plumber works for 3 hours. Work out how much she charges.

(b) The plumber does a job that costs £135. Work out how long the job takes. Give your answer in hours and minutes.

Example

v = u + at

(a) Find u if v = 13, a = 2 and t = 3

(b) Find a if v = 4, u = 19 and t = 5.

L.O. - To substitute into formulae and use equation solving to find values.

Starter

v = u + at

Find the value of v if:

(a) u = 3, a = 5, t = 2

v = 13

(b) u = -4, a = 2, t = 10

v = 16

(c) u = -5, a = 0.5, t = -8

v = -9

Example

v = u + at

(a) Find u if v = 13, a = 2 and t = 3

13 = u + 6

u = 7

(b) Find a if v = 4, u = 19 and t = 5.

4 = 19 + 5a

-15 = 5a

-3 = a

Example

A plumber uses the formula C = 25h + 30 to work out how much to charge customers, based on the number of hours she works.

(a) The plumber works for 3 hours. Work out how much she charges.

C = 25(3) + 30

C = 75 + 30

C = 105

(b) The plumber does a job that costs £135. Work out how long the job takes. Give your answer in hours and minutes.

135 = 25h + 30

105 = 25h

4.2 = h

4 hours 12 minutes = h

Activity

Complete the equations and formulae worksheet

Activity

Complete the equations and formulae worksheet

1. p = 1

2. t = 5

3. n = 2

4. p = 28

5. p = 0.125

6. t = 0.142857...

7. a = 1.2

8. b = 0.75

9. p = 1.5

10. p = 3.3333...

1. p = 0.75

2. k = 10/13

3. w = 2/3

4. p = 0.5

5. m = -2

6. g = 1.25

7. a = 2/3

8. t = 1

9. c = 3

10. w = 1.25

1. a = 0.8

Plenary

Plenary

1)

(a) 70 mins

(b) 100 mins

(c) 17 lb

2)

(a) c = 165

(b) c = 305

(c) n = 25

**Activities**

**Activity**

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