Question

What is the kinetic energy of a 4-kg toy car moving at a velocity of 8 m/s?

O 32J
64 J
O
128 J
256 J

Answer 1

Mass of toy the car = 4 kg

Velocity of toy the car = 8 m/s

Kinetic energy of an object is the energy that it possesses due to its motion.

Kinetic energy is directly proportional to the mass of the object and to the square of its velocity.

Formula of Kinetic energy:

`\boxed{ \bf{KE = (1)/(2)mv^2}}`

KE → Kinetic energy of the Object (J)

m → Mass of the Object (kg)

v → Speed of the Object (m/s)

By substituting values in the formula, we get:

`\rm \longrightarrow KE = (1)/(2) * 4 * 8^2 \\ \\ \rm \longrightarrow KE = (1)/(2) * 4 * 64\\ \\ \rm \longrightarrow KE = 2 * 64 \\ \\ \rm \longrightarrow KE = 128 \: J`

`\therefore` Kinetic energy of the toy car = 128 J

Answer 2

128 J

Step-by-step explanation:

The kinetic energy of an object can be found by using the formula

`k = (1)/(2) m {v}^(2) \\`

m is the mass

v is the velocity

From the question we have

`k = (1)/(2) * 4 * {8}^(2) \\ = 2 * 64`

We have the final answer as

128 J

Hope this helps you