Question

(b)
A bird of mass 2 kg is flying at an altitude of 100 m with a speed of 5 ms. Calculate the
mechanical energy of the bird. (g - 10 ms?)
​

Answer 1

Mass of the bird (m) = 2 kg

Altitude of flying (h) = 100 m

Speed of flying (v) = 5 m/s

Acceleration due to gravity (g) = 10 m/s²

★ Mechanical Energy ( M.E ) : Energy is neither created nor destroyed , it only changes from one state of energy to other state . It is two types ,

➤ Potential Energy ( P.E ) : Energy held by an object because of it's position relative to other objects .

➤ Kinetic Energy ( K.E ) : Energy of an object because of it's motion or energy gained by an object from it's state of rest to motion .

➠ M.E = P.E + K.E

➠ M.E = mgh + ¹/₂ mv²

➠ M.E = (2)(10)(100) + ¹/₂ (2)(5)²

➠ M.E = 2000 + 25

➠ M.E = 2025 J $\star$

Mechanical energy of the bird is 2025 Joules .

Answer 2

Answer:

• The mechanical energy of the bird is 2025J.

Explanation:

Given that,

• Mass of bird (m) = 2 kg
• Altitude of flying (h) = 100 m
• Speed of flying (v) = 5 m/s
• Acceleration due to gravity (g) = 10 m/s²

_________________

$\red \bigstar \boxed{ \sf Potential \: Energy (P.E) = mgh}$

[ Putting values ]

$\sf \leadsto \: P.E = 2 \times 10 \times 100 \\ \\ \leadsto \sf \: P.E = 20 \times 100 \\ \\ \sf \leadsto \: P.E = 2000J \: \: \purple \bigstar$

_________________

$\green\bigstar \boxed{ \sf Kinetic \: Energy (K.E) = \frac{1}{2}mv^{2}}$

[ Putting values ]

$\sf \leadsto \: K.E = \frac{1}{2} \times 2 \times (5) {}^{2} \\ \\ \leadsto \sf \:K.E = 25 J \: \: \pink \bigstar$

We know that,

$\large \green \bigstar \boxed{\sf Mechanical \: Energy (M.E) = Potential \: Energy (P.E) + Kinetic \: Energy (K.E) </p><p>}$

[ Putting values ]

$\leadsto \sf \: M.E = 2000 + 25J \\ \\ \: \: \: \: \: \: \: \: \: \: \: \leadsto \sf \: M.E = 2025J \: \: \red \bigstar$