A bullet fired vertically upward from a gun held 2m above the ground, reaches its maximum height in 4s. Calculate the

Physics Jamb, Waec, Neco Past Questions & Answers on Speed, Velocity and Acceleration

Questions 51: A bullet fired vertically upward from a gun held 2m above the ground, reaches its maximum height in 4s. Calculate the;

(i) magnitude of the initial velocity of the bullet,

(ii) total distance the bullet travelled by the time it hits the ground. [g=lOm/s] 

NECO 2006 Ans: (i) 40m/s (n) 162m

SOLUTIONS 

Solving for (I)

• initial velocity u= ?
• Acceleration due to gravity g= 10m/s²
• Distance of bullet s, 2m
• Time to reach maximum heights t = 4s
• At maximum height, 
• final velocity, v = 0 
• thus from v = u - gt

0 = u - gt

∴ u = at 

u = 10 x 4 

u = 40 mls