Question

block of mass 2 kg moving at a speed of 20 metre per second accelerates at 2 metre per second for 5 seconds find its final kinetic energy​

Answer 1

Given:

• Mass= m = 2kg
• Initial velocity = u = 20m/sec
• Acceleration= a = 2m/${sec}^{2}$
• Time = t = 5sec

━━━━━━━━━━━━━━━━

Need to find:

• Kinetic energy =?

━━━━━━━━━━━━━━━━

Solution:

From 1st equation of motion, we know:-

v= u+ at

$\rightarrow \: v = 20 + 2 \times 5 \: m/s$

→ v= 20 + 10 m/sec

→ v = 30 m/sec

━━━━━━━━━

We know,

Kinetic energy= $\dfrac{1}{2} m {v}^{2}$

→ KE= $\dfrac{1}{2} \times 2 \times 30 \times 30$

→ KE = 30 × 30 Joules

→ KE = 900 Joules

Answer 2

$\huge\mathfrak{\color{red}{\underline{\underline{solutíón♡}}}}$

Given:

• Mass= m = 2kg
• Initial velocity = u = 20m/sec
• Acceleration= a = 2m/s².
• Time = t = 5sec

━━━━━━━━━━━━━━━━

Need to find:

Kinetic energy =?

━━━━━━━━━━━━━━━━

From 1st equation of motion, we know:-

V = u+at

$\rightarrow \: v = 20 + 2 \times 5 m\s$

⠀⠀⠀⠀⠀

⠀⠀⠀⠀⠀⠀

→ v= 20 + 10 m/sec

→ v = 30 m/sec

━━━━━━━━━

We know,

⠀⠀⠀⠀⠀

⠀⠀⠀⠀⠀⠀

Kinetic energy= $\dfrac{1}{2} m {v}^{2}$

→ KE= $\dfrac{1}{2} \times 2 \times 30 \times 30$

→ KE = 30 × 30 Joules

→ $\red{\boxed{\bold{\large{KE=900Joules}}}}$