Solving Physics Question: Momentum Change of 0.42 kg Ball

[draconicspectre]

A 0.42 kg ball is moving horizontally with a speed of 5.5 m/s when it strikes a vertical wall. The ball rebounds with a speed of 2.0 m/s. What is the magnitude of the change in linear momentum of the ball?

Might seem like a simple problem, but everytime i input an answer into it, it says I am wrong, can neone help?

 

[radou]

A 0.42 kg ball is moving horizontally with a speed of 5.5 m/s when it strikes a vertical wall. The ball rebounds with a speed of 2.0 m/s. What is the magnitude of the change in linear momentum of the ball?

Might seem like a simple problem, but everytime i input an answer into it, it says I am wrong, can neone help?

Since the change in linear momentum is a vector given by (mv2-mv1)i, its magnitude is the square root of (mv2-mv1)^2, which equals mv2-mv1. This should work.

 

[kyle8921]

I would approach this problem by first understanding the concept of linear momentum. Linear momentum is defined as the product of an object's mass and its velocity. In this case, the 0.42 kg ball has an initial momentum of 0.42 x 5.5 = 2.31 kg*m/s in the horizontal direction before it strikes the wall.

After the collision, the ball rebounds with a speed of 2.0 m/s in the opposite direction. This means that its final momentum is 0.42 x (-2.0) = -0.84 kg*m/s. The negative sign indicates that the ball's momentum has changed direction.

To find the magnitude of the change in linear momentum, we can simply calculate the difference between the initial and final momenta. This would be 2.31 - (-0.84) = 3.15 kg*m/s. This means that the magnitude of the change in linear momentum of the ball is 3.15 kg*m/s.

It is important to note that the direction of the change in momentum is opposite to the initial momentum, as the ball is rebounding in the opposite direction. This concept is in accordance with the law of conservation of momentum, which states that the total momentum of a system remains constant unless an external force acts upon it.

In conclusion, the magnitude of the change in linear momentum of the 0.42 kg ball is 3.15 kg*m/s in the opposite direction. It is crucial to understand the concepts of momentum and conservation of momentum in order to solve such physics problems accurately.