Question

A car has a mass of 800kg and a momentum of 14000kgm/ s. What is its kinetic energy? *
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Answer 1

S O L U T I O N :

Given :- A car has a mass of 800kg and a momentum of 14000 kg.m/s.

We know that,

Momentum = Mass × Velocity

[ Put the values ]

⟶ 14000 = 800 × Velocity

⟶ Velocity = 14000/800

⟶ Velocity (v) = 17.5 m/s

Now, we need to find the it's kinetic energy,

As we know that,

K.E = ¹/2 × mv²

Where,

• K.E = Kinetic energy
• m = Mass
• v = Velocity

[ Put the values ]

⟶ K.E = ¹/2 × 800 × (17.5)²

⟶ K.E = 400 × 306.25

⟶ K.E = 122500 J

Therefore,

The kinetic energy of car is 122500 joule.

Answer 2

Question :-

A car has a mass of 800kg and a momentum of 14000kgm/ s. What is its kinetic energy?

Answer :-

• Kinetic energy of car = 122500 joule

Given :-

• Mass of the car = 800 kg
• Momentum = 14000kg m.s

Have to find :-

• What is its kinetic energy?

Solution :-

We know the formula to find kinetic energies :-

↬ K.E = ½ × mv²

Here ,

" m " = Mass of the object

" v " = Velocity of object

In order to find kinetic energy , we need to know Velocity first :-

We know ,

Velocity = Momentum / Mass

So , Substituting the values

14000/800

↬ $(v)$ = 17.5 m/s

So , simply fíndíng kinetic energy now ,

↬ K.E = ½ × 800 × (17.5)²

↬ K.E = 400 × 306.25

↬ K.E = 122500 Joules