Question

A car expends an energy of 2500 J while moving at a speed of 50 m/s. What is the mass of the car?

Answer 1

Answer :.

• The mass of the car is 2 kg.

Explanation :

Given :

• Kinetic energy possessed by the car, K.E. = 2500 J
• Velocity of the car, v = 50 m/s

To find :

• Mass of the body, m = ?

Knowledge required :

By definition, Kinetic energy possessed by a body is due to State of rest.

and,

Formula for Kinetic energy :

⠀⠀⠀⠀⠀⠀⠀⠀⠀K.E. = ½mv²

Where,

• K.E. = Kinetic energy of the body
• m = Mass of the body
• v = Velocity of the body

Solution :

By using the equation for Kinetic energy possessed by a body and substituting the values in it, we get :

⠀⠀⠀=> K.E. = ½mv²

⠀⠀⠀=> 2500 = ½ × m × 50²

⠀⠀⠀=> 2500 = ½ × m × 2500

⠀⠀⠀=> 2500 = m × 1250

⠀⠀⠀=> 2500/1250 = m

⠀⠀⠀=> 2 = m

⠀⠀⠀⠀⠀⠀⠀⠀⠀∴ m = 2 kg

Therefore,

• Mass of the body, m = 2 kg.

Answer 2

Answer:

Given :-

• A car expands an energy of 2500 J while moving at a speed of 50 m/s.

To Find :-

• What is the mass of the car.

Formula Used :-

To find the mass we have to use kinetic energy formula,

$\bold{\boxed{\small{Kinetic\: energy\: =\: \dfrac{1}{2}m{v}^{2}}}}$

where,

• m = Mass of the body
• v = Velocity of the body

Solution :-

Given :

• K.E = 2500 J
• v = 50 m/s

According to the question by using the formula we get,

⇒ $\dfrac{1}{2}$ × m × (50)² = 2500

⇒ $\dfrac{1}{2}$ × m × 2500 = 2500

⇒ 1250 × m = 2500

⇒ m = $\sf\dfrac{\cancel{2500}}{\cancel{1250}}$

➠ m = 2 kg

∴ The mass of the car is 2 kg .