Question

154. A ball is thrown vertically upwards with a velocity
of 40 m/s. What is the velocity of the ball after two
second ? (g = 10 m/s2)​

Answer 1

Answer:

Given:

Initial velocity of ball = 40 m/s

Gravitational acceleration = 10 m/s²

To find:

Velocity of the ball after 2 seconds.

Formulas used:

v = u + at

a => acceleration , u => initial velocity ,

v => final Velocity and t => time

Calculation:

Now, acceleration will be considered as

- 10 m/s² . ( Negative sign indicated the opposite direction of gravity with respect to the initial velocity)

v = u + at

=> v = 40 + {(-10) ×2}

=> v = 40 - 20

=> v = 20 m/s

$\huge{\boxed{final \: answer \: = 20 \: m {s}^{ - 1} }}$

Answer 2

$\Large{\underline{\underline{\red{\mathfrak{Answer :}}}}}$

Final velocity (v) = 20 m/s

$\large{\underline{\underline{\red{\mathfrak{Step-By-Step-Explanation :}}}}}$

$\tt Given \begin{cases} \sf{Initial \: velocity \: (u) \: = \: 40 \: ms^{-1}} \\ \sf{Time \: (t) \: = \: 2 \: s} \\ \sf{Gravitation \: Force \: (g) \: = \: 10 \: ms^{-2}} \end{cases}$

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To Find :

Final Velocity of the ball (v)

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Solution :

We have formula :

$\Large{\underline{\boxed{\rm{v \: = \: u \: + \: at}}}}$

Where,

v is final velocity

u is initial velocity

a is acceleration

t is time interval

We will take here a = -g = -10 m/s² because in this case ball is thrown vertically upwards. So, the role of acceleration will be played by gravitational force,

Put Values

⇒v = 40 + (-10(2))

⇒v = 40 + 20

⇒v = 20

$\LARGE \implies {\boxed{\boxed{\sf{v \: = \: 20 \: ms^{-1}}}}}$

∴ Final Velocity will be 20 m/s

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