Question

A ball of mass 2 kg is throw up with a speed of 10 m/sec . Find the kinetic energy of ball at the time of throwing . Also find the potential energy of ball at the highest point ?
please tell in explanation​

Answer 1

Given :-

Mass of the ball = 2 kg

Initial velocity = 10 m/s

To Find :-

The kinetic energy of ball at the time of throwing.

The potential energy of ball at the highest point.

Solution :-

We know that,

• u = Initial velocity
• m = Mass
• KE = Kinetic energy
• v = Final velocity
• PE = Potential energy

Using the formula,

$\underline{\boxed{\sf Kinetic \ energy=\dfrac{1}{2}m(v^2-u^2) }}$

Given that,

Final velocity (v) = 0 m/s

Mass (m) = 2 kg

Initial velocity (u) = 10 m/s

Substituting their values,

⇒ KE = (1/2) × 2 (0² - 10²)

⇒ KE = (1/2) × 2 (0 - 100)

⇒ KE = 1/2 × 2 × -100

⇒ KE = -200/2

Since KE cannot be negative,

⇒ KE = 100 J

Therefore, the kinetic energy of ball at the time of throwing is 100 J.

We know that,

Sum of kinetic energy and potential energy is equal at any point while it is being thrown up.

ie. Sum of kinetic energy = Height

Given that,

Potential energy = Height = 0 J

Kinetic energy (KE) = 100 J

Substituting them,

Sum of potential and kinetic energy= 0 + 100

Sum = 100 J

Using the formula,

$\underline{\boxed{\sf Maximum \ point=KE+PE}}$

Given that,

Kinetic energy (KE) = 0 J

Maximum point = 100 J

Substituting their values,

⇒ -100 = 0 + PE

⇒ PE = Maximum point + KE

⇒ PE = 100 + 0

⇒ PE = 100 J

Therefore, the potential energy of ball at the highest point is 100 J.