Tim Gan Math
Sign up free

Finding the value of an unknown in a formula

Finding the value of an unknown in a formula

Secondary 2

The time, \(t\) seconds, for a ball dropped from a height of \(h\) metres to reach the ground is modelled by \(t=\sqrt{\dfrac{h}{4.9}}\).

  1. Find \(t\) when \(h=19.6\).
  2. Find \(h\) when \(t=3\).
  3. A student substitutes \(t=-2\) and obtains \(h=19.6\). Explain why this value of \(t\) is not possible.

Solution:

Solution locked

680+ questions here come with free worked solutions. A free account saves your questions and progress; this one needs a course plan.

Create free accountSign inGet the E Math course · from S$29.98/moE Math tuition

Create a free account to practise similar questions.

Create free accountSign inGet the E Math course · from S$29.98/moE Math tuition
Answer:(a) \(t=2\) (b) \(h=44.1\) (c) A square root is never negative, so \(t\) cannot be \(-2\).

Need help? Join our E-Maths tuition for O-Level success.

Learn more