Question

The answer that I get is 80 kg, but what answer key says is the answer is 5 kg. Solve please.

Answer 1

hey it's a simple one....
as u can see it is told that the mass will stop after the application of force on it...

now u can solve it by this method....

as u can see.....(-F) = ma...
-10= 2.5 × a
a = -4 ms(2)...
negative sign represents retardation....

but the final velocity will be 0

a = v- u /t
-4 = 0 -20 / t
t = 5 sec....

Answer 2

F=ma. F=m*(v/t). Substitute the values , 10=2.5*(20/t). t=2.5*20/10=5s. If it helps u , mark it as brainliest