Question

Please explain the last line of this slide(the one which I have marked) as it is unclear and I think even wrong.(100 points)

Answer 1

Answer:

No, it is not wrong.

Explanation:

The explaination(starting from the last line) is as follows.

$f \: \alpha \frac{m(v - u)}{t}$

$or \: f \: \alpha \: ma$

$or \: f \: = kma$

where k is the propotionality constant. After this scientist at that time decided to define the unit of force i.e. 1N as the force required to accelerate a 1kg mass by 1 m/s². So in this system of unit

1N = k(1kg)(1m/s²)

or k = 1

Scientist defined 1N in such a manner to make k= 1 as it makes the equation simpler.If they defined 1N in a different way, the value of k would have been something else. I hope this clear up your confusion.

Answer 2

where k is the propotionality constant. After this scientist at that time decided to define the unit of force i.e. 1N as the force required to accelerate a 1kg mass by 1 m/s². So in this system of unit1N = k(1kg)(1m/s²)or k = 1Scientist defined 1N in such a manner to make k= 1 as it makes the equation simpler.If they defined 1N in a different way, the value of k would have been something else. I hope this clear up your confusion.