Question

Calculate the kinetic energy of a 70 kg person moving at a speed of 5m/s

Answer 1

`\boxed {\boxed {\sf 875 \ Joules}}`

Step-by-step explanation:

Kinetic energy is the energy an object possesses due to motion. It is calculated using the following formula:

`KE= (1)/(2)mv^2`

The mass of the person is 70 kilograms and they are moving at a speed of 5 meters per second.

• m= 70 kg
• v= 5 m/s

Substitute these values into the formula.

`KE= (1)/(2) (70 \ kg )(5 \ m/s)^2`

Solve the exponent.

• (5 m/s)² = 5 m/s * 5 m/s = 25 m²/s²

`KE= (1)/(2)(70 \ kg)(25 \ m^2/s^2)`

Multiply the numbers in parentheses.

`KE= (1)/(2) (1750 \ kg*m^2/s^2)`

Multiply by 1/2 or divide by 2.

`KE= 875 \ kg*m^2/s^2`

Convert the units. 1 kilogram meter squared per second squared is equal to 1 Joule. So, our answer of 875 kg*m²/s² is equal to 875 Joules.

`KE= 875 \ J`

The person has 875 Joules of kinetic energy.

Answer 2

875 J

Step-by-step explanation:

The kinetic energy of an object can be found by using the formula

`k = (1)/(2) m {v}^(2) \\`

m is the mass

v is the velocity

From the question we have

`k = (1)/(2) * 70 * {5}^(2) \\ = 35 * 25 \\ = 875`

We have the final answer as

875 J

Hope this helps you