Question

If a ball is thrown vertically upwards with $40m/s$ its velocity after two seconds will be:-

Answer 1

Step 1: List the given values,

Initial velocity of the ball $u=40m/s$

Time period $t=2s$

It is acted upon by acceleration due to gravity $g$ in the downward, which is the opposite direction of motion of ball,

$\therefore a=-g$

Where $g=10m/s^2$

Step 2: Calculate final velocity,

We know that the final velocity from the first equation of motion is given as,

$v=u+at$

Upon substituting the values we get,

$v=40+\left(-10\right)2$

$=40-20$

$=20m/s$

Hence, the final velocity of the ball after two seconds will be $20m/s$ will be in the upwards direction.