Question

A stone is vertically thrown upward with the velocity of 72 km/hr. Find the maximum height reached and time taken to reach the height.

Answer 1

Answer:

Hope it helps!

Explanation:

u = 72 km/h = 72 × 5/18 = 20 m/s

v = ?

a = -9.8 m/s²

t = ?

Answer 2

Given :-

• Initial Velocity (u) = 72 km/hr
• Final Velocity (v) = 0 m/s
• Acceleration due to gravity (g) = -10 m/s

To Find :-

• The maximum height reached and time taken to reach the height.

Solution :-

★ First we have to convert Initial Velocity (u) 72 km/hr to m/s :

→ Initial Velocity (u) = 72 × 5/18

→ Initial Velocity (u) = 20 m/s

Now,by using first equation of motion we get :

⋗ v = u + at

⋗ 0 = 20 + (-10)t

⋗ 0 = 20 - 10t

⋗ -20 = -10t

⋗ t = -20 ÷ -10

⋗ t = 20 ÷ 10

⋗ t = 2 s

Now,by using second equation of motion we get :

⇢s = ut + ½ at²

⇢s = 20 × 2 + ½ × -10 × (2)²

⇢s = 40 + ½ × -10 × 4

⇢s = 40 -10 × 2

⇢s = 40 - 20

⇢s = 20 m

Therefore,

• The maximum height reached by stone = 20 m
• and time taken by it to reach the height = 2 s