a 20N object falls 10 meters. how many joules of kinetic energy does the object gain?


a)10
b) 20
c) 200
d) 2000

(c) m •g •h =(m•g) •h=20•10=200 J

200

To calculate the kinetic energy gained by the object, we can use the formula:

Kinetic Energy = (1/2) * mass * velocity^2

However, in this case, we are given the force acting on the object (20N) instead of its mass or velocity. Therefore, let's first calculate the force.

We can use Newton's second law of motion to find the force:

Force = mass * acceleration

In this case, since the object is falling freely near the Earth's surface, we can assume the acceleration due to gravity as approximately 9.8 m/s^2.

20N = mass * 9.8 m/s^2

Now, solve for the mass:

mass = 20N / 9.8 m/s^2

mass ≈ 2.04 kg (rounded to two decimal places)

Now, let's calculate the velocity of the object when it falls 10 meters.

The formula for calculating the final velocity after falling from a given height is:

velocity = √(2 * acceleration * height)

In this case, the acceleration is the same as before (9.8 m/s^2), and the height is 10 meters.

velocity = √(2 * 9.8 m/s^2 * 10 m)

velocity ≈ √(196 m^2/s^2)

velocity ≈ 14 m/s (rounded to two decimal places)

Finally, let's calculate the kinetic energy gained by the object using the formula mentioned earlier:

Kinetic Energy = (1/2) * mass * velocity^2

Kinetic Energy ≈ (1/2) * 2.04 kg * (14 m/s)^2

Kinetic Energy ≈ 20 * (14 m/s)^2

Kinetic Energy ≈ 20 * 196 m^2/s^2

Kinetic Energy ≈ 3920 J

Therefore, the object gains approximately 3920 joules of kinetic energy.

The correct answer choice is not given among the options a), b), c), or d).

To find the joules of kinetic energy gained by an object, we need to use the formula:

Kinetic Energy = 1/2 * mass * velocity^2

However, in this case, we are given the weight of the object, not its mass. Since the weight is given by the force of gravity acting on the object's mass, we can use the formula:

Weight = mass * gravitational acceleration

In this case, the weight is 20N and the object falls 10 meters. We can rearrange the above formula to solve for mass:

mass = weight / gravitational acceleration

The gravitational acceleration on Earth is approximately 9.8 m/s^2. Substituting the given values, we have:

mass = 20N / 9.8 m/s^2 ≈ 2.04 kg

Now, we can substitute the calculated mass into the formula for kinetic energy:

Kinetic Energy = 1/2 * mass * velocity^2

Since the object is falling, its initial velocity is 0 m/s. Thus, the formula simplifies to:

Kinetic Energy = 1/2 * mass * 0^2 = 0

Therefore, the object gains 0 joules of kinetic energy as it falls. None of the given options (a) 10, (b) 20, (c) 200, (d) 2000) are correct.