Question

Please tell me the answer

Answer 1

Kinetic energy = 0.16 J

As we know that ,

• Momentum = Mass × velocity

Now ,

✧ p = 0.5 × v

✧ 0.4/0.5 = v

✧ (4/10)/(5/10) = v

✧ 4/5 = v

✧ Velocity = 0.8 m/s

As we know that ,

• Kinetic energy = 1/2 mv²

☆ K.E = 1/2 × 0.5 × 0.8²

☆ K.E = 1/4 × 4/5 × 4/5

☆ K.E = 1/5 × 4/5

☆ K.E = 4/25

★ K.E = 0.16 J ★

Answer 2

Question -

✠ A body of mass 0.5 kg has a momentum of 0.4 kgm/s. Find it's kinetic energy.

Given that -

✠ Mass of the body = 0.5 kg

✠ Momentum = 0.4 kgm/s

To find -

✠ Kinetic energy.

Solution -

✠ Kinetic energy = 0.16 Joules

Using concept -

✠ Formula to find kinetic energy

✠ Formula to find momentum (to find velocity) because in kinetic energy formula we need to use velocity.

Using formula -

✠ Kinetic energy = ½ mv²

✠ Momentum = m × v

Where,

★ m denotes mass

★ v denotes velocity

Full solution -

~ Let's find the velocity by using formula to find momentum.

⇢ Momentum = m × v

⇢ 0.4 = 0.5 × v

⇢ 0.4/0.5 = v

⇢ (4/10)/(5/10) = v

⇢ 4/5 = v

⇢ 0.8 = v

⇢ v = 0.8 m/s

• Henceforth, 0.8 m/s is the velocity.

~ Let us find kinetic energy now,

⇢ Kinetic energy = ½ mv²

⇢ Kinetic energy = ½ × 0.5 × (0.8)²

⇢ Kinetic energy = ½ × 0.5 × 0.8 × 0.8

⇢ Kinetic energy = ½ × 0.5 × 0.64

⇢ Kinetic energy = ½ × 0.320

⇢ Kinetic energy = ½ × 320/1000

⇢ Kinetic energy = ½ × 32/100

⇢ Kinetic energy = 16 / 100

⇢ Kinetic energy = 8 / 50

⇢ Kinetic energy = 4/25

⇢ Kinetic energy = 0.16 J

More knowledge -

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