Physics momentum and impulse questions

In summary, the conversation discusses an 8.0 N force acting on a 5.0 kg object for 3.0 seconds. The questions ask for the impulse given to the object, the change in momentum caused by the impulse, and the final velocity of the object if its initial velocity is 25 m/s. The definition of impulse is discussed, and the equation for impulse and change in momentum is given. The units of momentum are also mentioned.
  • #1
Ereny
29
0
an 8.0 N force acts on a 5.0 kg object for 3.0 sec. what impulse is given to the object? what change in momentum does to his impulse cause? if the object's initial velocity is 25 m/s determine the final velocity of the object?

i have the right answers because my teacher gave them to use .. but i don't know how to get there.. am i suppose to combine both masses? and use the impulse equation which is p=f.t ??

i am really confused and i would really appreciate any help thanks.

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  • #2
Ereny said:
an 8.0 N force acts on a 5.0 kg object for 3.0 sec. what impulse is given to the object? what change in momentum does to his impulse cause? if the object's initial velocity is 25 m/s determine the final velocity of the object?

This is all really straightforward. It is asking you for the impulse. Well, what is the definition of impulse?
 
  • #3
isn't it a force.. i am really confused btw the meaning of impulse and momentum
 
  • #4
Ereny said:
an 8.0 N force acts on a 5.0 kg object for 3.0 sec. what impulse is given to the object? what change in momentum does to his impulse cause? if the object's initial velocity is 25 m/s determine the final velocity of the object?

i have the right answers because my teacher gave them to use .. but i don't know how to get there.. am i suppose to combine both masses?
There is only one mass mentioned here, there is no other mass to "combine" it with.
and use the impulse equation which is p=f.t ??
If an impulse acts on a body it causes a change of momentum of that body. Equate the impulse to the change of momentum as: F·∆t = m·∆v

Q: what are the units of momentum?
 
  • #5


First of all, it is important to understand the definitions of momentum and impulse in physics. Momentum is the product of an object's mass and velocity, and it is a measure of the object's motion. Impulse, on the other hand, is the force applied to an object over a period of time, and it is equal to the change in momentum of the object.

In this scenario, an 8.0 N force acts on a 5.0 kg object for 3.0 seconds. To find the impulse given to the object, we can use the equation I = FΔt, where I is the impulse, F is the force, and Δt is the time. Plugging in the values given, we get I = (8.0 N)(3.0 sec) = 24 Ns.

This impulse causes a change in momentum of the object. To find the change in momentum, we can use the equation Δp = mΔv, where Δp is the change in momentum, m is the mass of the object, and Δv is the change in velocity. Since the object's initial velocity is 25 m/s, and we know that the impulse is equal to the change in momentum, we can rearrange the equation to solve for the final velocity. This gives us Δv = I/m = (24 Ns)/(5.0 kg) = 4.8 m/s. Therefore, the final velocity of the object is 25 m/s + 4.8 m/s = 29.8 m/s.

In summary, to solve this problem, we used the impulse equation I = FΔt to find the impulse given to the object, and then used the fact that impulse is equal to the change in momentum to find the change in momentum. Finally, we used the equation Δp = mΔv to solve for the final velocity of the object. It is important to understand the concepts of momentum and impulse in order to solve problems like this in physics.
 

FAQ: Physics momentum and impulse questions

1. What is the difference between momentum and impulse?

Momentum is a property of an object that is determined by its mass and velocity, while impulse is the change in an object's momentum over time. In simple terms, momentum is the quantity of motion an object has, while impulse is the force applied to an object to change its motion.

2. How is impulse related to force?

Impulse is directly proportional to force, meaning that the greater the force applied to an object, the greater the change in its momentum. This is represented by the equation impulse = force x time, where time is the duration of the force applied.

3. Can momentum be negative?

Yes, momentum can be negative. This occurs when an object is moving in the opposite direction of its defined positive direction. For example, if a car is moving to the left with a velocity of -10 m/s, its momentum would be -10 kg m/s.

4. How is momentum conserved in a closed system?

Momentum is conserved in a closed system, meaning that the total momentum of all objects before a collision or interaction is equal to the total momentum after the collision or interaction. This is known as the law of conservation of momentum.

5. What are some real-life applications of momentum and impulse?

Momentum and impulse are important concepts in many areas of physics, including mechanics, electromagnetism, and thermodynamics. Some real-life applications include designing car safety features, understanding the motion of objects in space, and determining the optimal angle for a pool ball to strike the cushion and pocket a target ball.

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