Q) A stone is thrown vertically upwards with a speed of 49 m/s. Then the velocity of the stone, one second before it reaches the maximum height is
A) 4.9 m/s B) 9.8 m/s C) 13.6 m/s D) 19.6 m/s
Answers & Comments
kartiktyagi11
The acceleration due to gravity = 9.8 m/s/s According to newton's first equation of motion: v = u + at where v = final velocity, u = initial velocity, a = acceleration and t = time taken v = 0 m/s (at maximum height) a = -9.8 m/s/s (deaccelerating) t = 1 s 0 = u - 9.8 -> u = 9.8 m/s Thus, the ans is (b)
Answers & Comments
According to newton's first equation of motion:
v = u + at
where v = final velocity, u = initial velocity, a = acceleration and t = time taken
v = 0 m/s (at maximum height)
a = -9.8 m/s/s (deaccelerating)
t = 1 s
0 = u - 9.8
-> u = 9.8 m/s
Thus, the ans is (b)