Question

What is the KE of a 4500kg at a speed of 20 m/s?

Answer 1

$\\ \maltese \: \: \: \: \large{\underline{\underline{\pmb{ \textbf{\textsf{\color{purple}{Given \: :}}}}}} }$

• Mass ( m ) of the body = 4,500 kg
• velocity of the body = 20 m/s

$\\ \maltese \: \: \: \: \large{\underline{\underline{\pmb{ \textbf{\textsf{\color{green}{To \: Find \: :}}}}}} }$

• kinetic energy (ke) = ??

$\\ \maltese \: \: \: \: \large{\underline{\underline{\pmb{ \textbf{\textsf{\color{aqua}{Solution \: :}}}}}} }$

★ Calculating the kinetic energy;

$\\ \maltese \: \: \: \: \large{\underline{\underline{\pmb{ \textbf{\textsf{\color{hotpink}{using \: formula \: :}}}}}} }$

$\red\bigstar { \underline{ \underline{\underline{\boxed{\color{blue}{\sf{ \:Kinetic \: \: energy \: = \frac{1}{2} \: \: m \: v \: {}^{2} }}}}}} }$

Where ,

• (Ke) = kinetic energy.
• m = mass
• v = velocity

$\\\\\sf \implies \: \:Kinetic \: \: energy \: = \frac{1}{2} \: \: m \: v \: {}^{2}$

$\\\sf \implies \: \:Kinetic \: \: energy \: = \frac{1}{2} \: \times \: 4,500 \: \times \: { 20}^{2}$

$\\\sf \implies \: \:Kinetic \: \: energy \: = \frac{1}{2} \: \times \: 4,500 \: \times \: 400$

$\\\sf \implies \: \:Kinetic \: \: energy \: = \frac{1}{ \cancel{2}} \: \times \: \cancel {4,500 }\: \times \: 400$

$\\ \sf \implies \: \:Kinetic \: \: energy \: = 2,250 \: \times \: 400$

$\\\bf \implies{ \pink{ \: \:Kinetic \: \: energy \: = 9,00,000 \: \: \: joules}}$

hence the kinetic energy (ke) is 9,00,000 Joules...!!

Answer 2

Answer:

900kJ

Explanation:

The formula to find the kinetic energy is :

$E_k=\frac{1}{2} mv^{2}$

Here,

m ⇒ mass ⇒ 4500 kg

v ⇒ velocity ⇒ 20 m/s

Let us find it now.

$E_k=\frac{1}{2} mv^{2}$

$E_k=\frac{1}{2} *4500*20^{2}$

$E_k=\frac{1}{2} *1800000$

$E_k=900000J$

$E_k=900kJ$