Question

A 1.0-kilogram rubber ball traveling east at 4.0 meters per second hits a wall and bounces back toward the west at 2.0 meters per second. Compared to the kinetic energy of the ball before it hits the wall, the kinetic energy of the ball after it bounces off the wall is

Answer 1

Answer:

8 J and 2 J

Explanation:

Given that,

Mass of the rubber ball, m = 1 kg

Initial speed of the rubber ball, u = 4 m/s (in east)

Final speed of the rubber ball, v = -2 m/s (in west)

We need to find the kinetic energy of the ball before it hits the wall, the kinetic energy of the ball after it bounces off the wall.

Initial kinetic energy,

$K_i=\dfrac{1}{2}mv^2\\\\K_i=\dfrac{1}{2}\times 1\times (4)^2\\\\K_i=8\ J$

Final kinetic energy,

$K_f=\dfrac{1}{2}mv^2\\\\K_f=\dfrac{1}{2}\times 1\times (2)^2\\\\K_f=2\ J$

So, the initial kinetic energy is 8 J and the final kinetic energy is 2 J.

Answer 2

The kinetic energy of the ball after it bounces off the wall is 2.0 Joules.

The kinetic energy of an object is the energy that is in motion or performing work. It can be expressed by using the formula:

$\mathbf{K.E = \dfrac{1}{2}mv^2}$

• The mass of the object(rubber ball) = 1.0 kg
• The initial speed of the rubber ball before the collision = 4.0 m/s
• The final speed of the rubber ball after the collision = - 2.0 m/s

The Kinetic energy of the ball after the collision and when it bounces off the wall is computed as:

$\mathbf{K.E = \dfrac{1}{2} \times 1 \times 2.0^2}$

K.E = 2.0 Joules

Learn more about kinetic energy here:

https://brainly.com/question/8101588