A cricket ball is thrown vertically upward with an initial velocity of 40ms-1 find. 1. It's velocity after 3se.
2.The maximum height attained and the time taken to reach it.

As we gain mass the force of gravity on us increases!

Ithink the answer is d

Newton's first law describes something special that results from the sum of all the external forces (including gravity) on an object. 

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.