Answer:
a) - 25.43 m/s
b) H = 0.815 m
t = 0.41 s
Step-by-step explanation:
Given that:
Initial velocity (u) = 4 m/s, and the acceleration due to gravity (g) = 9.81 m/s²
a) For a body thrown upward, gravity acts on the body and causes a decrease in velocity as it continues to move, making the body to reach a maximum height and start falling. The formula for a vertically thrown object is:
v = u - gt
t = time = 3 s and v = final velocity.
Therefore:
v = 4 - (9.81 × 3) = - 25.43 m/s
b) The equation is given as:
v² = u² - 2gH
Where H is the maximum height. At maximum height, final velocity v = 0. Therefore:
2gH = u²
H = u² / 2g
H = 4² / 2(9.81) = 0.815 m
Given that v = u - gt and at maximum height, v = 0
Therefore t = u / g = 4 / 9.81 = 0.41 s