Conservation of momentum on bike

In summary, Tony, who weighs 45kg, is riding his bike, which weighs 5kg, at a constant speed of 1 m/s. He is also carrying a 5kg pack. When he throws the pack forward at a speed of 5 m/s relative to the bike's speed, the bike's speed changes. The equation used to solve the problem was (50)(1) + (5)(1) = (50)(v) + (5)(5), but the solution was incorrect. Further clarification is needed.
  • #1
Momentum09
71
0

Homework Statement



Tony (45kg) coasts on his bike (5kg) at a constant speed of 1 m/s, carrying a 5kg pack. Tony throws his pack forward, in the direction of his motion, at 5 m/s relative to the speed of bike just before the throw. What is the bike speed immediately after the throw?

Homework Equations



mv1 + mv1 = mv2 + mv2


The Attempt at a Solution



I combined Tony and the bike's mass together, 50kg. I then did
(50)(1) + (5)(1) = (50)(v) + (5)(5) and solved for v. However that wasn't correct. Can somebody please tell me what I did wrong?

Thank you so much!
 
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  • #2
Please read the following carefully.

Momentum09 said:
at 5 m/s relative to the speed of bike

Relativity is your friend. :wink:
 
  • #3
thanks so much! :)
 

What is conservation of momentum on bike?

Conservation of momentum on bike is a physical law that states that the total momentum of a system, in this case a bike and rider, remains constant unless acted upon by an external force. This means that the momentum of the bike and rider combined will not change unless there is a force acting on them, such as friction or an impact.

How does conservation of momentum apply to biking?

In biking, conservation of momentum is observed when the rider and bike are in motion. As the rider pedals, the bike gains momentum and the rider's body also gains momentum. When the rider brakes, the momentum of the bike and rider decreases, but it is conserved as the energy is transferred to the brakes and the ground.

What factors affect conservation of momentum on a bike?

The main factors that affect conservation of momentum on a bike include the mass of the bike and rider, the speed at which they are traveling, and external forces such as air resistance and friction. The direction and angle of the bike's movement can also affect conservation of momentum.

How can conservation of momentum be used in biking?

Conservation of momentum can be used in biking to improve efficiency and performance. For example, by using proper techniques and positioning, a rider can conserve their momentum and maintain a steady speed, reducing the need for constant pedaling. Additionally, understanding conservation of momentum can help prevent accidents and crashes by knowing how to control and adjust the bike's momentum.

Are there any exceptions to conservation of momentum on a bike?

While conservation of momentum is a fundamental physical law, there are some exceptions when it comes to biking. For instance, when biking on a curved path, the direction of the bike and rider's momentum may change, but the total momentum of the system is still conserved. Additionally, when biking up or downhill, gravity can play a role in affecting the conservation of momentum. However, in most cases, conservation of momentum still applies to biking.

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