Question

On an object of mass 1kg moving along x-axis with constant speed 8m/s ,a constant force 2N is applied in opposite y-direction. Find its speed after 4 seconds.

Answer 1

Speed along X axis is, vx = 8 m/s

Mass, m = 1 kg

Force applied, Fy = 2 N

Acceleration, ay = F/m = 2/1 = 2 m/s2

Now, along Y the body starts moving after application of the force.

Initial velocity along Y, uy = 0

So, using, v = u + at

=> vy = uy + ayt

=> vy = 0 + (2)(4)

=> vy = 8 m/s

So, magnitude of the resultant velocity is,

v = (vx2 + vy2)1/2 = (82 + 82)1/2 = 8√2 m/s