Question

If the blocks are placed on smooth
plane as shown in figure. If they are
released simultaneously on smooth
plane, then find exerted (R) by 20 kg
block on 5 kg block:
0-300​

Answer 1

Answer:

Explanation:

ANSWER

By applying force balance equation on all the three free masses  

The acceleration of all the three masses = a

let all the three masses are a system of 7 kg moving in one direction

So, the acceleration of all the masses is same as combined mass,

a=  

totalmass

netforce

​  

 

a=  

2+4+1

120−50

​  

=  

7

70

​  

=10

 

Apply force balance equation to all the masses individually

formass1kg

120−N  

1

​  

=1X10

120−N  

1

​  

=10

N  

1

​  

=110N

formass4kg

N  

1

​  

−N  

2

​  

=4X10

N  

1

​  

−N  

2

​  

=40

hereN  

1

​  

= 110N

then,N  

2

​  

= 110−40=70N

for mass 2kg net force in the direction of N  

2

​  

 then net force on mass 2kg is  

F=N  

2

​  

−50

F=70−50=20N