Calculate the resultant of the pair of velocities 100 km/h north and 75 km/h south. Calculate the resultant if both of the velocities are directed north. ?

Answer : 2 2 2 As We know that: Resultant vector is given by R A + B + 2ABcos ……….(1) Now here we have to find the resultant of the velocities which are in the same direction,So the angle between the two vectors is zero, therefore cos 0 = 1 Now substitute the value of cos cos = 1 2 2 We get R = A + B + 2AB ……………(2) Now here a= 100 km/h, b= 75 km/h substitute these values in equation (2) We get R = 100 + 75 + 2(100 × 75 )……………(3) R = 123.1 m/s Resultant velocity we be R = 123.1 m/s