Question

A force Of 100 N stops a body moving with a velocity of 20ms^-1. The force required to stop the same
body wan moving with 30 ms^-1 in the same distance is
A)550N
B)225N
C)112.5N
D)65N
Note :Dont any silly questions then i will follow u​

Answer 1

Explanation:

distance traveled in both the cases is equal and also both the objects will come to rest after covering this much of distance

mass is also same for both the objects

case 1

using Newton's third equation of motion

2as=v²-u²

2as=0-(20)²

2as=-400

a=-200/s eq1

Force=mass*acceleration

F=m*a

100=m*(-200/s) using eq1

m=(-s)/2 eq2

case 2

again using Newton's third equation of motion

2as=v²-u²

2as=0-(30)²

a=-450/s eq2

now

Force=mass*acceleration

F=-s/2*(-450)/s

cancelling s with s

we get 225 N option B