Question

If the present units of length, time and mass (m, s, kg) are changed to 100m, 100s, and $\frac{1}{10}$kg then

• A. The new unit of velocity is increased 10 times
• B. The new unit of force is decreased $\frac{1}{1000}$ times
• C. The new unit of energy is increased 10 times
• D. The new unit of pressure is increased 1000 times

Answer 1

Answer: (B)

The new unit of force is decreased $\frac{1}{1000}$ times

Answer 2

Unit of velocity = m/sec ; in new system =$\frac{100m}{100\sec\frac{m}{\sec}}$ (same)

Unit of force $= \frac{kg \times m}{\sec^{2}}$; in new system

$= \frac{1}{10}kg \times \frac{100m}{100\sec \times 100\sec}$ $= \frac{1}{1000}\frac{kg \times m}{\sec^{2}}$

Unit of energy $= \frac{kg \times m^{2}}{\sec^{2}}$ ; in new system

$= \frac{1}{10}kg \times \frac{100m \times 100m}{100\sec \times 100\sec}$ $= \frac{1}{10}\frac{kg \times m^{2}}{sec^{2}}$

Unit of pressure $= \frac{kg}{m \times \sec^{2}}$; in new system

$= \frac{1}{10}kg \times \frac{1}{100}m \times \frac{1}{100sec \times 100sec} = 10^{- 7}\frac{kg}{m \times sec^{2}}$