A particle of mass 120 g moving at speed of 750 cm/s is acted upon by a variable force opposite to its direction of motion. If the velocity of the particle becomes 250 cm/s along the direction of force, find the value of time 't' for which force acted.

A particle of mass 120 g moving at speed of 750 cm/s is acted upon by

1.	A particle of mass 120 g moving at speed of 750 cm/s is acted upon by a variable force opposite to its direction of motion. If the velocity of the particle becomes 250 cm/s along the direction of force, find the value of time 't' for which force acted.
Answer» Solution :AREA of FT GRAPH = Impulse = change in MOMENTUM `(1)/(2)(t+6)xx10^(-2)xx10` `= 120xx10^(-3)(7.5+2.5)` `therefore t=18 s`