A rock is thrown upward with a velocity of 17 meters per second from the top of a 31 meter high cliff and it missies the cliff on the way back down when will the rock ve 8 meters from the ground level

Step-by-step explanation:

t = Time taken

u = Initial velocity =17 m/s

v = Final velocity

s = Displacement

a = Acceleration

g = Acceleration due to gravity = 9.81 m/s² = a

Total height the rock is to fall when it is 8 meters from the ground is

Time taken to reach the maximum height is 1.73 s.

Time taken from the maximum height to the point which is 8 m from the ground is 2.77 s.

So, time taken from the moment of the throw to the point 8 m from the ground is .

Ananya's total score was 50 marks.

Step-by-step explanation:

Given that in an examination a candidate scored 5 marks for a correct answer, -2 for an incorrect answer and 0 marks for a question that has not been attempted, and the examination comprises 20 questions, and Ananya has answered 12 correct answer and 5 incorrect answers, to find her total score the following calculation must be performed:

(12 x 5) + ((20 -12 - 5) x 0) + (5 x -2) = X

60 + (3 x 0) + (-10) = X

60 + 0 - 10 = X

50 = X

Therefore, Ananya's total score was 50 marks.