Question

A bowling ball of mass 10. kg is dropped from a height of 10. m When it is 5.0 m above the ground,
what is the total energy of the ball? Neglect air resistance, give your answer in joules to two significant
figures and without a unit. Take g as 9.81 m 5-2​

Answer 1

Answer:

according to the law of conservation of energy the total energy contained by the body will remain same at all points

Explanation:

in Newton energy = 98.1N

it it can't be expressed in Joule because

Answer 2

The total energy of the bowling ball at a height of 5 m is 9.8 × 10² Joules.

Given:

Mass of the bowling ball (m) = 10 kg

Height from which its dropped (H) = 10 m

Height up to which it falls (h) = 5 m

g = 9.81 ms⁻²

To Find:

The total energy of the bowling ball at a height of 5 m above the ground.

Solution:

→ According to the Law of conservation of energy for a system the total energy of a system remains conserved, it only changes its form from one form to another.

→ In the case of a freely falling body, the mechanical energy which is the sum of potential energy (U) and kinetic energy (K) remains conserved. Hence for a freely falling body, the total energy which is the sum of potential energy and kinetic energy at any instant always remains constant.

Potential energy of the ball at a height of 10 m (U₁) = mgH = 10 × 9.81 × 10

                                           ∴ U₁ = 981 J

The kinetic energy of the ball at a height of 10 m (K₁) = 0

Potential energy of the ball at a height of 5 m (U₂) = mgh = 10 ×9.81 ×5

                                          ∴ U₂ = 490.5 J

By the law of conservation of energy the total mechanical energy will remain constant:           

                                     ∵ U₁ + K₁ = U₂ + K₂

                                     ∴ 981 + 0 = 490.5 + K₂

                                         ∴ K₂ = 490.5 J

Hence at a height of 5 m above the ground, the Kinetic energy (K₂) is equal to 490.5 J and the Potential energy (U₂) is equal to 490.5 J.

Therefore at a height of 5 m above the ground, the total energy of the ball will be equal to 981 Joules or 9.81 × 10² Joules.

Now converting it into two significant figures:

Therefore the total energy of the bowling ball at a height of 5 m above the ground would be equal to 9.8 × 10² Joules.

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