A 600kg car is at rest, and then it accelerates to 5 m/s. What is the original kinetic energy?
What is its final kinetic energy?
How much work was used?

1. 0 J

2. 7500 J

3. 7500 J

Explanation:

From the question given above, the following data were obtained:

Mass (m) of car = 600 Kg

Initial velocity (v₁) of car = 0 m/s

Final velocity (v₂) of car = 5 m/s

Original kinetic energy (KE₁) =?

Final kinetic energy (KE₂) =?

Work used =?

1. Determination of the original kinetic energy.

Mass (m) of car = 600 Kg

Initial velocity (v₁) of car = 0 m/s

Original kinetic energy (KE₁) =?

KE₁ = ½mv₁²

KE₁ = ½ × 600 × 0²

KE₁ = 0 J

Thus, the original kinetic energy of the car is 0 J.

2. Determination of the final kinetic energy.

Mass (m) of car = 600 Kg

Final velocity (v₂) of car = 5 m/s

Final kinetic energy (KE₂) =?

KE₂ = ½mv₂²

KE₂ = ½ × 600 × 5²

KE₂ = 300 × 25

KE₂ = 7500 J

Thus, the final kinetic energy of the car is 7500 J

3. Determination of the work used.

Original kinetic energy (KE₁) = 0

Final kinetic energy (KE₂) = 7500 J

Work used =?

Work used = KE₂ – KE₁

Work used = 7500 – 0

Work used = 7500 J

No, it will not fall. The pencil will remain at zero speed relative to the spacecraft and will orbit the earth with the spacecraft.