2 persons a and b are working with speed 4km/hr and 5 km/hr in the same directions. Find how far will be b from a after 3 hours?

Person a:

Distance d_a = vt = 4 km/h × 3 h = 12 km

 

Person b:

Distance d_b = vt = 5 km/h × 3 h = 15 km

 

Thus, b will be 3 km away from a after 3 hours.

 

 

Important derivations:

1) To derive the three kinematical equations.

 

2) To derive the equation of path of projectile.

 

3) To derive time of flight of a projectile, and also maximum height reached and horizontal range of projectile.

 

4) Maximum speed of a vehicle on a banked road.

 

5) Derive the work energy theorem for a variable force.

 

6) Expression of speed of two particles after elastic collision between the two.