Question

1) a particle moves 3m north. 4m east and finally 6m south. calculate the displacement.

2) state the si unit of speed. a girl moves with the speed of 6km/hr for 2 hours and with the speed of 4 km/h for the next three hours. find the average speed of the girl and the total distance moved.

Answer 1

1st.....
so finally the particle has moved 3m south and 4m east
so displacement will be
=√[(3)²+(4)²]
=√[9+16]
√[25]
=5
2nd.....
si unit of speed is m/s
distance travelled in 1st 2hrs by girl =speed×time
=6×2
=12km
and distance travelled in next 3hrs
=4×3
=12km
for average speed
=(total distance)/(total time)
=(12+12)/(2+3)
=24/5kmph