Answer:
Force = 18N
Explanation:
Force = [ mass ( final velocity - initial velocity ) ] / time taken
using the formula, here mass is 3 kg, final velocity = 45 m/s , initial velocity = 45 m/s , time taken = 2 seconds
Force = [ 3 ( 45 - 33 ) ] / 2
Force = 18N
The ideal mechanical advantage of the pulley system is 3
Answer:
The ratio of electric force to the gravitational force is 
Explanation:
It is given that,
Distance between electron and proton, 
Electric force is given by :

Gravitational force is given by :

Where
is mass of electron, 
is mass of proton, 
is charge on electron, 
is charge on proton, 



So, the ratio of electric force to the gravitational force is
. Hence, this is the required solution.