You buy a plastic dart gun, and being a clever physics student you decide to do a quick calculation to find its maximum horizontal range. you shoot the gun straight up, and it takes 4.6 s for the dart to land back at the barrel.

Explanation:

When we shoot the dart upwards the time taken by the dart to go straight up and again come back is given as

here we can say

put t = 4.6 s then we have

Now in order to find the maximum range we can say

so in order to have maximum range we can say