The reading on a spring balance with a holder and eight identical discs is 3.0N. Six discs are removed and the reading becomes 1.2N.
0
1
2
3
4
N spring
balance
holder
for discs
eight
discs
two
discs
0
1
2
3
4
N
What is the weight of one disc?
A 0.2N B 0.3N C 0.5N D 0.6N

The brightest star in the night sky in the northern hemisphere is sirius. its distance from earth is estimated to be 8.7 light years. a light year is the distance light travels in one year. light travels at a speed of 3.00 × 108 m/s. calculate the distance from earth to sirius in miles. (1 mi = 5280 ft) g