# A force of 20N acts on a body of mass 4kg at rest. What is the accelaration of the body? What is the velocity after 10sec if the same force acts? After 10sec if the force ceases to act how will the body move?plz urgentttttttttttttt

2
by crmail

2015-04-12T20:40:43+05:30
F=ma
a=F/m
a=20/4
acceleration=5 m/s2

2015-04-12T21:00:46+05:30

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Force = F = 20 Newtons
Mass = m = 4 kg
initial velocity u = 0
acceleration a = force / mass = F / m
= 20 / 4 = 5 meters/sec²

velocity v = u + a t
v = 0  + 5 m/sec² * 10 sec = 50 m/sec

During the first 10 seconds when the force is acting on the body, the body accelerates continuously.  That is its speed increases every instant.  At 1 sec its speed is 5 m/s,  at 2 sec, its speed is 10 m/s,  at 3 sec, its speed is 15 m/s ....

when the force ceases to act at 10 sec, then the body continues to move along the straight line (as per the 1st law of Newton).  it moves with a constant velocity of 50 m/sec.  this is the inertia of motion.