# A 9.7"kg" mass is positioned on top of a vertical spring. What is the upward force exerted on the mass by the spring?

Nov 20, 2016

${F}_{s p} = 85 N$

#### Explanation:

Use Newton's second law, which (in summary) states that $F = m a$. Assuming no friction and that the mass is given in kilograms,

${F}_{s p} = 9.7 k g \cdot 8.8 \frac{m}{s} ^ 2$

${F}_{s p} = 85 N$

Nov 27, 2016

Net downward force on the 9.7 kg mass ${F}_{n} = 9.7 \times 8.8 N$

Gravitational force on the 9.7 kg mass ${F}_{g} = 9.7 \times 9.8 N$

If the upward force exerted by spring be ${F}_{s}$ then

${F}_{n} = {F}_{g} - {F}_{s}$

$\implies {F}_{s} = {F}_{g} - {F}_{n} = 9.7 \times 9.8 - 9.7 \times 8.8 = 9.7 N$