# What is the kinetic energy of a 9 kg object moving at 5/4 m/s?

Apr 1, 2018

$\text{7.03 J}$

#### Explanation:

$\text{K.E" = 1/2\ "mv"^2 = 1/2 × "9 kg" × (5/4\ "m/s")^2 = 225/32\ "J" = "7.03 J}$

Apr 2, 2018

Approximately $7.03$ joules.

#### Explanation:

Kinetic energy is expressed through the equation,

$\text{KE} = \frac{1}{2} m {v}^{2}$

• $m$ is the mass of the object in kilograms

• $v$ is the velocity of the object in meters per second

So, we plug in the values into the given equation, and we get

"KE"=1/2*9 \ "kg"*(1.25 \ "m/s")^2

$= 4.5 \setminus {\text{kg"*1.5625 \ "m"^2"/s}}^{2}$

$= 7.03125 \setminus \text{J}$

$\approx 7.03 \setminus \text{J}$

Apr 2, 2018

I retained answer in fractions as the velocity is given in fractions.

#### Explanation:

Kinetic energy is given by the expression for a body of mass $m$ moving with velocity $v$

$K E = \frac{1}{2} m {v}^{2}$

Inserting given values we get

$K E = \frac{1}{2} \times 9 \times {\left(\frac{5}{4}\right)}^{2}$
$K E = \frac{225}{32}$
$K E = 7 \frac{1}{32} \setminus J$