Question

A ball of the mass 200g is thrown upward with an initial velocity of 30 m/s how long will it take to reach the highest point?

Answer 1

V final velocity u initial velocity g accln due to gravity and t time

-ve symbol because speed reduces when thrown upward due to gravity.

then we will use

KE = 1/2 m v2

From 1st eqn we get v= 19 m/ s

and from 2nd eqn we will get

KE= 36.1 J

Let me know if i am wrong somewhere

Answer 2

Mass = 200 g

Velocity = 30 m/s

Let maximum height be h.

Time = ?

By Laws of Motion

v² = 2 g h

⇒ ( 30 )² = 2 × 10 × h

⇒ 900 = 20 h

⇒ h = 900/20

⇒ h = 45

Height = 45 m

Velocity = 30 m/s

S = ut + 1/2 at²

u = 0

S = h

h = 1/2 g t²

⇒ t² = 2 h/g

⇒ t² = 2 × 45/10

⇒ t² = 45/5

⇒ t² = 9

⇒ t = 3

The time is 3 s .