Exam-style Questions: Units, Quantities and Measurements

1. Here is a list of five units for physical quantites.

kgm-3

Nm-2

Cs-1

Ω m

Ws

From the list

a) write down the unit for electrical current ................

b) write down the unit for mechanical stress ................

(2 Marks)

(Marks available: 2)

Answer outline and marking scheme for question: 1

a) Cs-1

b) N m-2

(2 Marks)

(Marks available: 2)

2. Here is a list of five units

J

N

Jkg-2

Nkg-1

From the list write down the correct unit for

a) the energy stored in a stretched spring ................

b) centripetal force ................

(Marks available: 2)

Answer outline and marking scheme for question: 2

a) the energy stored in a stretched spring .............J...

b) centripetal force .........N.......

(Marks available: 2)

3. The acceleration, a, of a body in simple harmonic motion is given by:

a = - (2πf)2x

Where f if frequency of the oscillation and x is the displacement.

Show that the right hand side of the equation has the units of acceleration.

(Marks available: 2)