Answer:
it will be 3 seconds
Explanation:
initial horizontal velocity of the rock, u = 20 m/s
horizontal distance traveled by rock, R = 60 m
The the range of the projectile is given by;
R = vt
where;
v is the initial horizontal velocity of the rock
t is the time spent by the rock in air
t = R/v
t = 60 / 20
t = 3 s
