Finding the magnitude of velocity vector

In summary, the problem involves calculating the range of a ball thrown by a cricketer with a force of 7.5N for 0.84s at a launch angle of 39 degrees from horizontal. The range equation is used to solve for the range, but the magnitude of the velocity vector needs to be found first. The acceleration is determined to be 51.02 m/s^2 and the velocity is calculated to be 42.86 m/s. Trigonometry is then used to find the horizontal and vertical components of the velocity, and the time value is calculated using the suvat equation. The final range is given as 225.52m, which is the displacement in the x-axis when the y-axis
  • #1
SpiraRoam
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Homework Statement


A cricketer throws a 147g ball by exerting a force of 7.5N for 0.84s. If the launch angle is 39 degrees from horizontal, calculate the range of the ball.

Homework Equations

The Attempt at a Solution


I have the range equation and I just need to find the magnitude of the velocity vector but I'm not sure how I'd find that with the given quantities?
 
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  • #2
What is the answer given in solutions section?
 
  • #3
Day3091 said:

Homework Statement


A cricketer throws a 147g ball by exerting a force of 7.5N for 0.84s. If the launch angle is 39 degrees from horizontal, calculate the range of the ball.

Homework Equations

The Attempt at a Solution


I have the range equation and I just need to find the magnitude of the velocity vector but I'm not sure how I'd find that with the given quantities?
Can you determine the acceleration ?
 
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  • #4
I thought it was a=f/m = 51.02m/s^2 and then v=at for 42.86 ms^-1 I was going to use a particular formula for range

The solution in the back of the mock exam says f=ma rearranged for m x deltav/deltat

Which is then rearranged for deltav = Fdeltat / m = 42.8 ms

Trigonometry to then find the Vx and Vy components which can then be plugged into t = v-u/a giving us a time value. This completes the vertical plane suvat.

Horizontal 'range' was simply given as displacement s=vt: 42.8(cos39) x 6.78 = 225.52m

upload_2017-6-9_20-58-45.png

When would this equation for range be applicable? It's defined as 'the displacement in the x-axis when the y-axis displacement is 0.' I imagine there is still some displacement for this scenario even though it doesn't end in the y axis? Making this equation irrelevant?
 

Related to Finding the magnitude of velocity vector

1. What is the magnitude of a velocity vector?

The magnitude of a velocity vector is the speed of an object in a particular direction. It is a scalar quantity and is represented by the length of the arrow in a velocity vector diagram.

2. How is the magnitude of a velocity vector calculated?

The magnitude of a velocity vector is calculated using the Pythagorean theorem, where the magnitude is equal to the square root of the sum of the squared components of the vector. In other words, it is the square root of the sum of the squares of the x and y components of the vector.

3. What is the unit for the magnitude of a velocity vector?

The unit for the magnitude of a velocity vector is typically meters per second (m/s), since velocity is a measure of distance traveled over time.

4. How does the magnitude of a velocity vector differ from its direction?

The magnitude of a velocity vector describes the speed of an object, while the direction describes the path or trajectory of the object. Both are necessary to fully describe a velocity vector.

5. Can the magnitude of a velocity vector be negative?

Yes, the magnitude of a velocity vector can be negative. This indicates that the object is moving in the opposite direction of the vector's direction. However, the magnitude itself is always a positive value.

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