Physics And Measurement Question 226
Question: In a certain system of units, 1 unit of time is 5 sec, 1 unit of mass is 20 kg and 1 unit of length is 10m. In this system, one unit of power will correspond to-
Options:
A) 16 watts
B) $ \frac{1}{16} $ watts
C) 25 watts
D) $ \frac{1}{25} $ watts
Show Answer
Answer:
Correct Answer: A
Solution:
[a]
$1 \text{ unit of time} = 5 \text{ seconds} $
$1 \text{ unit of mass} = 20 \text{ kg} $
$1 \text{ unit of length} = 10 \text{ meters}$
$\text{Force} F = \frac{\text{mass} \times \text{distance}}{\text{time}^2} $
$F = \frac{20 \text{ kg} \times 10 \text{ m}}{(5 \text{ s})^2} = \frac{200 \text{ kg} \cdot \text{m}}{25 \text{ s}^2} = 8 \text{ N}$
$\text{Work} W = \text{Force} \times \text{distance} $
$W = 8 \text{ N} \times 10 \text{ m} = 80 \text{ joules}$
$\text{Power} P = \frac{\text{Work}}{\text{time}} $
$P = \frac{80 \text{ joules}}{5 \text{ s}} = 16 \text{ watts}$
BETA
