Solve 2 Physics Problems: Vectors, Hockey Puck Motion

In summary, the first conversation discusses determining the x and y components of three vectors in the xy plane, including a displacement vector, a velocity vector, and a force vector. The second conversation involves calculating the vertical component of the initial velocity, the time it takes to reach a wall, and the horizontal component, initial speed, and angle of a puck in a hockey game. The questioner struggled with understanding the first problem but eventually figured it out, and also needed assistance with the second problem.
  • #1
neutron star
78
1
1.

Homework Statement

Determine the x and y components of the following three vectors in the xy plane.
(a) A 9-m displacement vector that makes an angle of 35° clockwise from the +y direction.
x: ____ m
y: ____ m

(b) A 25-m/s velocity vector that makes an angle of 45° counterclockwise from the -x direction.
x: ____ m/s
y: ____ m/s

(c) A 49-lb. force vector that makes an angle of 140° counterclockwise from the -y direction.
x: ____ lb
y: ____ lb





2.

You are watching your friend play hockey. In the course of the game, he strikes the puck in such a way that, when it is at its highest point, it just clears the surrounding 2.84 m high Plexiglas wall that is 10.8 m away. (Ignore any effects due to air resistance.)
(a) Find the vertical component of its initial velocity.
v0y = ____ m/s

(b) Find the time it takes to reach the wall.
Δt = ____ s

(c) Find the horizontal component of its initial velocity, and its initial speed and angle.
v0x = ____ m/s
v0 = ____ m/s
θ = ____ °



Homework Equations





The Attempt at a Solution

 
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  • #2
The rules of this forum clearly state
On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given. Under no circumstances should complete solutions be provided to a questioner, whether or not an attempt has been made.

Please follow them.
 
  • #3
Ok, I need help with the first one. I'm trying to set it up but I don't get what it's asking for. Can you help explain?

Ok, I figured it out, I set it up on paper and got it.
 
  • #4
I got the first one. I saw to get x you do sin(35) and then multiply by 9. And the same with y but cos instead of sin. I did the same thing for (b) in the first problem and it wasn't right. It's a velocity vector instead of a displacement vector. What difference does thi make for finding the solution?
 
  • #5
Make a drawing. Are there any negative components?
 

1. What are vectors and how are they used in physics?

Vectors are quantities that have both magnitude and direction. In physics, they are used to represent physical quantities such as displacement, velocity, and force. They are useful in solving problems involving motion and forces because they allow us to analyze both the magnitude and direction of these quantities.

2. Can you give an example of solving a physics problem using vectors?

Sure, let's say we have a hockey puck sliding on a frictionless surface at a constant speed of 5 m/s. We can represent the velocity of the puck as a vector with a magnitude of 5 m/s and a direction of motion. If the puck then hits a patch of ice with a coefficient of kinetic friction of 0.2, we can use vectors to calculate the change in its velocity due to the friction force and determine its new speed and direction of motion.

3. How do you add or subtract vectors?

To add or subtract vectors, we use the head-to-tail method or the parallelogram method. In the head-to-tail method, the tail of the second vector is placed at the head of the first vector, and the resultant vector is drawn from the tail of the first vector to the head of the second vector. In the parallelogram method, the vectors are represented as sides of a parallelogram, and the diagonal of the parallelogram represents the resultant vector. The direction of the resultant vector can be determined by the angle between the vectors.

4. How can vectors be used to solve problems involving projectiles?

Vectors are essential in solving projectile motion problems. The initial velocity of the projectile can be represented as a vector, and the acceleration due to gravity can also be represented as a vector. By breaking these vectors into their x and y components, we can analyze the horizontal and vertical motion separately. This allows us to calculate the trajectory, range, and maximum height of the projectile.

5. Can vectors be used to solve problems in real-life scenarios?

Yes, vectors are used in many real-life scenarios, such as engineering, navigation, and sports. In the case of the hockey puck problem, understanding how vectors work can help a hockey player improve their shot accuracy and power. In engineering, vectors are used to calculate the forces acting on a structure and ensure its stability. In navigation, vectors are used to determine the direction and speed of a moving object, such as a ship or airplane.

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