Answer:
(a) 1.28 m
(b) 0.51 s
Explanation:
Given:
Initial speed, U = 5 m/s
Consideration;
1. When the coin is tossed upward, the coin is moving against gravity. Therefor, the acceleration due to gravity experienced by the coin is negative, -g = -9.8 m/s².
2. The final velocity of the coin in the air is zero.
From equation of motion under free fall,
V² = U² + 2gh
h = 
Where;
V is the final velocity
U is the initial velocity
g is the acceleration due to gravity
h is the height

h = 1.2755 m
h = 1.28 m
(b) The coin still has its initial velocity, u to be equal to 5 m/s, final velocity, v to be equal to 0 m/s and acceleration due to gravity to be -9.8 m/s while in the air before returning to the release point.
From equation of motion under free fall,
V = U + gt


t = 0.51 s