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3 years ago

How much kinetic energy does a 7.2-kg dog need to make a vertical jump of 1.2 m? (The acceleration due to gravity is 9.8 m/s2.)

Physics

2 answers:

V125BC [204]3 years ago

7 0

How much kinetic energy does a 7.2-kg dog need to make a vertical jump of 1.2 m?
Answer:

85 Joule (approx)

Explanation:

Potential energy at highest point

P.E = mgh = 7.2 kg × 9.8 m/s2×1.2 m≈85 Joule

This is the kinetic energy required for dog to jump a height of 1.2 m.

hope this helps!

Tasya [4]3 years ago

6 0

Answer:

Kinetic energy of dog is 84.67 Joules

Explanation:

Given that,

Mass of the dog, m = 7.2 kg

We have to find the kinetic energy does a 7.2-kg dog need to make a vertical jump of 1.2 m. We know that the energy of a system remains conversed. At highest point there is only potential energy. So, while taking a vertical jump the potential energy gets converted to potential energy.

So, $E_k=mgh$

here, h = 1.2 m

$E_k=7.2\times 9.8\times 1.2$

$E_k=84.67\ Joules$

Hence, the kinetic energy needed to make a vertical jump is 84.67 Joules.

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b) The velocity of the ball when it reaches its maximum height is 0.

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b) The velocity of the ball at maximum height is 0, because, in that moment, the ball does not go up nor down. Immediately after, the ball will start to fall with negative velocity.

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