Question

Plastic drum of cylindrical shape is made by melting spherical solid plastic balls of radius 1 cm . find the no. of balls required to make drum of thickness 2cm, height 90 cm and outer radius 30 cm

Answer 1

Step-by-step explanation:

Given: α,β are zeroes of the polynomial 4x

2

+3x+7

To find the value of

α

1

+

β

1

From the given quadratic equation,

α+β=−

4

3

and αβ=

4

7

Therefore,

α

1

+

β

1

=

αβ

α+β

=

4

7

−

4

3

=−

7

3

⇒

α

1

+

β

1

=−

7

3

Answer 2

Answer:

The volume of the drum would be volume of outer cylinder - volume of inner cylinder.

2) Outer radius = 30 cm, Inner radius = 30-2 = 28 cm.

3) Volume of the drum = π(30)²*90 - π(28)²*90 = π*90*116 = 10440π cm³

4) Volume of one plastic ball =4 πr³/3 = 4π/3 *(1)³ = 4π/3 cm³

5) Volume of n plastic balls = 4πn/3 cm³

6) Number of balls = 10440π/(4π/3) = 7830