Question

Question

Which object has the greatest kinetic energy?(1 point)
Responses

a red car mass of 500 kg moving at 3 m/s
a red car mass of 500 kg moving at 3 m/s

a yellow car with a mass of 500 kg moving at 12 m/s
a yellow car with a mass of 500 kg moving at 12 m/s

a green car with a mass of 500kg moving at 21 m/s
a green car with a mass of 500kg moving at 21 m/s

a blue car with a mass of 500 kg moving at 30 m/s
a blue car with a mass of 500 kg moving at 30 m/s
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Answer 1

The kinetic energy (KE) of an object can be calculated using the formula:

\[ KE = \frac{1}{2} mv^2 \]

where:

• \( m \) is the mass of the object,
• \( v \) is the velocity of the object.

Since all the cars have the same mass of 500 kg, we only need to compare their velocities to determine which one has the greatest kinetic energy.

Let's calculate the kinetic energy for each car:

1. Red car:
   \[ KE = \frac{1}{2} \times 500 \times (3)^2 = \frac{1}{2} \times 500 \times 9 = 2250 , \text{J} \]

2. Yellow car:
   \[ KE = \frac{1}{2} \times 500 \times (12)^2 = \frac{1}{2} \times 500 \times 144 = 36000 , \text{J} \]

3. Green car:
   \[ KE = \frac{1}{2} \times 500 \times (21)^2 = \frac{1}{2} \times 500 \times 441 = 110250 , \text{J} \]

4. Blue car:
   \[ KE = \frac{1}{2} \times 500 \times (30)^2 = \frac{1}{2} \times 500 \times 900 = 112500 , \text{J} \]

Now, comparing the kinetic energies:

• Red car: 2250 J
• Yellow car: 36000 J
• Green car: 110250 J
• Blue car: 112500 J

The blue car with a mass of 500 kg moving at 30 m/s has the greatest kinetic energy of 112500 J.