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(a) Rearrange this formula to make u the subject - OCR - GCSE Maths - Question 2 - 2023 - Paper 6
Question 2
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(a) Rearrange this formula to make u the subject.
$$v^2 = u^2 + 2as$$
(b) A rocket accelerates at 90 m/s² and travels 270 km.
The rocket's final velocit... show full transcript
Worked Solution & Example Answer:2
(a) Rearrange this formula to make u the subject - OCR - GCSE Maths - Question 2 - 2023 - Paper 6
Step 1
Rearrange this formula to make u the subject
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Answer
To rearrange the formula v2=u2+2as to make u the subject, we start by isolating u2 on one side:
Subtract 2as from both sides:
v2−2as=u2
Take the square root of both sides:
u=ext±sqrtv2−2as
This expression gives us the value of u.
Step 2
Using part (a), or otherwise, calculate the rocket's initial velocity
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Answer
From part (a), we have the formula:
u=ext±sqrtv2−2as
Given:
Final velocity v=8000m/s
Acceleration a=90m/s2
Distance s=270km=270000m
Now, substituting the values into the equation:
Calculate 2as:
2imes90imes270000=48600000
Now substituting in the rearranged formula:
u=ext±sqrt80002−48600000=ext±sqrt64000000−48600000=ext±sqrt15400000≈3932.0m/s
Since initial velocity cannot be negative, we choose the positive value:
u≈3932.0m/s