# What is the kinetic energy of an object with a mass of #7 kg# that has been in freefall for #3 s#?

Kinetic Energy

Kinetic Energy

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The kinetic energy of the object can be calculated using the formula:

[ KE = \frac{1}{2} m v^2 ]

Where:

- ( KE ) is the kinetic energy,
- ( m ) is the mass of the object, and
- ( v ) is the velocity of the object.

In freefall near the surface of the Earth, the velocity of the object can be approximated using the equation of motion:

[ v = g t ]

Where:

- ( g ) is the acceleration due to gravity (approximately ( 9.8 , \text{m/s}^2 )), and
- ( t ) is the time in seconds.

Substituting the values, we get:

[ v = (9.8 , \text{m/s}^2) \times 3 , \text{s} = 29.4 , \text{m/s} ]

Now, substituting the mass and velocity into the formula for kinetic energy:

[ KE = \frac{1}{2} \times 7 , \text{kg} \times (29.4 , \text{m/s})^2 ]

[ KE \approx 1029.3 , \text{J} ]

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When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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