A woman with a mass of 50 kg runs at a speed of 6 m / s and jumps onto a giant skateboard with a

A woman with a mass of 50 kg runs at a speed of 6 m / s and...

Key Concepts

Final Velocity Calculation

This involves determining the velocity of a system after a collision by dividing the total momentum by the total mass of the system. In problems where objects move together post-collision, the final velocity is computed by summing the individual momenta and then dividing by the combined mass.

Inelastic Collision

An inelastic collision is one in which the colliding bodies stick together after impact, moving as a single combined mass. Although kinetic energy is not conserved in such collisions, momentum conservation still applies, which allows for the calculation of the final velocity of the combined system.

Conservation of Momentum

This concept states that the total momentum of an isolated system remains constant if no external forces act upon it. In collision problems, the momentum before the event is equal to the momentum after the event, which allows us to determine unknown velocities or masses after collisions.

Momentum

Momentum is the product of an object's mass and its velocity. It is a vector quantity with both magnitude and direction, and it plays a crucial role in analyzing the motion of objects during interactions or collisions.

Transcript

00:01 In this question, we are wanting to find the combined speed of the woman after she has jumped onto the skateboard prior to running towards it.

00:09 So i'm going to begin by adding the information that we've been given in the question onto the diagram.

00:15 So we've been told that the woman has a mass of 50 kilograms and that she is running at a speed of 6 metres per second.

00:30 She then jumps onto a skateboard which has a mass of.

00:35 Of 30 kilograms and they move away together.

00:40 So prior to the woman jumping on the skateboard, the skateboard is stationary.

00:46 So they, it is moving at zero meters per second.

00:52 And we know that the mass of the woman and the skateboard must be the mass of the woman plus the mass of the skateboard.

01:00 So that is 50 kilograms plus 30 kilograms, which is equal to 80 kilograms.

01:08 Okay, so to answer this question, we're going to use the conservation of linear momentum.

01:14 We're going to use that to say that the momentum of the total system, that is the skateboard and the woman, before she's jumped on the skateboard, is equal to the total momentum of the woman and the skateboard afterwards.

01:25 And we know that this is the case because there is no external force acting on either of them.

01:31 So what we're going to do is calculate the total momentum of the system prior to the woman jumping on the skateboard...

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