QCEVault

Differential equations — Question 80

Original QCE Vault practice · 6 marks

Q80 · Practice questionComplex familiar6 marks

QUESTION 80 (6 marks)

An object cools in a room maintained at 22∘C22^\circ\mathrm C. Its temperature TT satisfies Newton’s law of cooling. Initially T=90∘CT=90^\circ\mathrm C, and after 10 minutes T=60∘CT=60^\circ\mathrm C.
a)
Determine the cooling constant kk in T=22+68e−ktT=22+68e^{-kt}.
[3 marks]
b)
Determine when the temperature first reaches 30∘C30^\circ\mathrm C.
[3 marks]
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