Find velocity of the vehicle:
A car having mass 400kg is moving with velocity of 20m/sec. A force of 200N that acts on it for 2 mins. Find velocity of the vehicle:
(1) When force acts in the direction of motion.
(2) When force acts in the opposite direction of motion.
Sol :
m = 400Kg, u = 20m/sec, F = 200N, t = 2min = 120sec, v =?
As F = ma
200 = 400 X a
a=0.5m/sec2 ...(i)
(1) Velocity of car after 120sec, When force acts in the direction of motion.
v = u + at
= 20 + 0.5 X 120
v = 80m/sec ........ANS
(2) Velocity of car after 120sec, when force acts in opposite direction of motion.
v = u - at
= 20 - 0.5 X 120
v = -40m/sec .......ANS
Negative sign indicate that body is moving in the reverse direction