Question

body of mass 2 kg is moving along positive X direction with a velocity of 5 metre per second now a force of 10 √ 2 newton is applied at an angle of 45 degree with x-axis it's velocity after 3s is

Answer 1

Initial velocity along X axis, Ux = 5 m/s

Acceleration upon the action of force = F cos θ / mass

= 10 √2 x (1/√2) / 2

= 10/2

= 5 m/s2.

Now, Vx = Ux + axt

Vx = 5 + [5 x 3]

Vx = 20m/s

Now, displacement alonf Y axis also needs to be considered as the force will displace the body from its straight line path.

So, Vy = Uy + ayt

Vy = 0 + 5 x 3 = 15 m/s

Now, resultant V = √(Vx2 + Vy2)

= √(202 + 152)

Thus,velocity after 3 sec = 25 m/s.