Question

A car of mass 1000kg is moving at a certain speed when a constant braking force 1000N acts on it for 5 sec and speed. Find the further time required to stop the car if the same constant force acts on it.

Answer 1

Answer:Retardation = Force/mass = 1000 N/ 1000 kg = 1 m/s2

Explanation:Retardation = Force/mass = 1000 N/ 1000 kg = 1 m/s2

in 5 seconds initial speed v0 reduces to (v0/2). then begin mathsize 12px style v subscript 0 over 2 equals v subscript 0 cross times 5 space minus space 1 half cross times 1 cross times 25 comma space t h i s space g i v e s space v subscript 0 equals space 25 over 11 end style

now the speed is (25/22) m/s. Required time to stop the car completely is given by

begin mathsize 12px style 0 space equals space 25 over 22 t space minus space 1 half cross times 1 cross times t squared space comma space t h i s space g i v e s space t space equals space 2 3 over 11 space s end style