2020HSCShort answer

Q12 (a) (iii)

2 marks

Question

Find the velocity of the box after the first three seconds.

Try the question before revealing the answer.

Solution

Criteria	Marks
Provides correct solution	2
Correctly obtains the acceleration, or equivalent merit	1

Sample answer:

From part (b), using $F=ma$ ,

50a=53.2

\therefore \frac{dV}{dt}=1.064

Hence the velocity after 3 seconds is

V=\int_0^3 1.064\,dt=1.064\times3=3.192\text{ m/s}

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Syllabus alignment

Mechanics

Modelling motion without resistanceApply forces, Newton's laws and calculus to model straight-line motion without resistance.

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