Mike walks 200 km in 6 hours. he then walks another 100km in 4 hours .what is his average speed?

Average speed is defined as the ratio of total distance covered in total given time

here we know that total distance that man moved is

so total distance is

now here total time of the motion is

total time will be given as

now by above formula

so his average speed is 30 km/h

think about the oscillation of the toy shown in the video. when the toy is at the highest point of its motion, its velocity is zero and its acceleration is negative.

conservation of mass

mass before something happens = mass afterwards