Physics # 2. A l m long uniform beam of 8ON weight is supported at the 60 cm mark by a pivot. Given that a mass of 10 kg hangs at the cm mark, at which position must another mass of 20 kg be hung to balance the beam? a) 19 cm b) 41 cm c) 79 cm d) none som man 3. A rickshaw puller pulls the rickshaw by applying a force of 180 N. If the rickaw moves with constant velocity of 90 km/h. ​

Well there is no derivation of this formula . It's no mathematical equation it's just basic principle to describe properties of objects that has mass .

It goes as follows that gravitational force F between two objects of mass m1 and M2 which are distance d apart is

F \propto \: m_{1}m _2F∝m

1

m

2

and

F \propto \frac{1}{ { d}^{2} }F∝

d

2

1

By combining these to equation we get

F \propto \frac{m_1m _2}{ {d}^{2} }F∝

d

2

m

1

m

2

When we remove the proptional sign there comes a constant G which is called gravitational constant

F = G\frac{m_1m _2}{ {d}^{2} }F=G

d

2

m

1

m

2

Value of G is

= 6.674 \times {10}^{ - 11} N {m}^{2} {(kg)}^{ - 2}=6.674×10

−11

Nm

2

(kg)

−2

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