Question

A particle of mass 1 kg is moving with constant velocity 20 m/s along a straight line. At t=0, a force F(t)=At starts acting on the particle, where t is time in seconds, F is in Newton, and A=2.0N/s. The direction of the force is always perpendicular to the velocity of the particle. If the velocity of the particle at t=0 and at t=5 is t0 and t5 respectively, the angle (in radians) between t(0) and t(5) is

Answer 1

Answer:

Given,

Mass=1kg

speed=8m/s

f=2N

t=4s

So,

Vx=8m/s ( velocity in x - axis ) 

Fy=2N ( force act on body in y-direction  

We know, 

F=ma

2=1×a

 

a=2m/s² In y- direction, 

Now, By using vector kinematics formula 

V=U+at

 

Here, 

U=8i,a=2j,t=4

V=8i+2j×4=8i+8j

Thus, final velocity = 8i + 8j 

Again,

We know, speed =∣velocity∣

 

speed=(82+82)=(2×82)

=82m/s