A ball is thrown vertically upwards from the ground with an initial velocity of 50m/s. What is the total time spent by the ball in the air? g.= 10m/s²

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

QUESTION 30. A ball is thrown vertically upwards from the ground with an initial velocity of 50m/s. What is the total time spent by the ball in the air? g.= 10m/s²

WAEC 1991 Ans: 10s

SOLUTIONS 

Initial velocity U= 50 m/s 

Acceleration due to gravity g= 10(always constant) 

Final velocity V=O (because the ball is thrown upward from the ground) 

time t= ?

Using v= u-gt

0=50-10×t,

0 = 50-10t

10t = 50-0

10t = 50

10t/10 = 50/10,

 t = 5s

Time taken to go upward is same as time taken to come down

Therefore t = 2 x 5 = 10s

Or 

Total time t= 5s+5s= 10s