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A dog has a speed of 7 m/s and a mass of 45 kg. What is the dog's kinetic energy?

A. 550.5 J
B. 157.5 J
C. 2205.0 J
D. 1102.5 J


Sagot :

Certainly! Let's walk through the process of finding the dog's kinetic energy step-by-step.

The formula for kinetic energy (KE) is:

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

where:
- [tex]\( m \)[/tex] is the mass of the object (in kilograms),
- [tex]\( v \)[/tex] is the velocity of the object (in meters per second).

Given:
- The dog's speed ([tex]\( v \)[/tex]) = 7 m/s.
- The dog's mass ([tex]\( m \)[/tex]) = 45 kg.

Substitute the given values into the kinetic energy formula:

[tex]\[ KE = \frac{1}{2} \times 45 \times (7)^2 \][/tex]

First, calculate the square of the speed:

[tex]\[ 7^2 = 49 \][/tex]

Next, multiply the mass by this squared speed:

[tex]\[ 45 \times 49 = 2205 \][/tex]

Now, take half of this product to find the kinetic energy:

[tex]\[ KE = \frac{2205}{2} = 1102.5 \][/tex]

So, the kinetic energy of the dog is:

[tex]\[ 1102.5 \, \text{J} \][/tex]

Therefore, the correct answer is:

D. 1102.5 J