The object at rest has an initial velocity >0?

In summary, the problem involves a grasshopper jumping 1.00 m from rest with an initial velocity at a 45.0 degree angle with respect to the horizontal. The goal is to find the initial speed and maximum height reached of the grasshopper. The acceleration in the x direction is considered constant, and the problem can be solved using basic kinematic equations and the simplified equation for x vector components. The question may be confusing due to the use of "from rest" but it is intended for the grasshopper to have an initial velocity.
  • #1
Who,me?

Homework Statement


A grasshoopper jumps 1.00 m from rest, with an initial velocity at a 45.0 degree angle with respect to the horizontal.
Find the initial speed of the grasshopper (answer is 3.13 m/s)
The maximum height reached (answer is .250m)


Homework Equations


acceleration in the x direction is considered constant, so you are using the basic kinematic equations, with a simplified equations for x vector components, e.g.
V0x=cos(0)

The Attempt at a Solution


The problem is that I can't figure out what they are asking. For example, up until now, in the class we have described an object at rest to have an initial velocity of zero. The question itself seems somewhat contradictory to me. What am I missing?
 
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  • #2
Who said:
acceleration in the x direction is considered constant...

Velocity in x direction is considered constant. Velocity in y direction is changing due to gravity. You just need to find the components, and then, using basic kinematic equations, find maximum height, distance, initial velocity, time...

Take a look at http://www.ngsir.netfirms.com/englishhtm/ThrowABall.htm" .
 
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  • #3
Who said:
The problem is that I can't figure out what they are asking. For example, up until now, in the class we have described an object at rest to have an initial velocity of zero. The question itself seems somewhat contradictory to me. What am I missing?
It's just an oddly phrased question. Despite the use of "from rest", they don't intend for the grasshopper to have an initial velocity of zero when he jumps. He was "at rest" sometime before he jumped. :wink:

A better phrasing would be something like: "A grasshopper jumps 1.00 m from its initial position, with an initial velocity at a 45.0 degree angle with respect to the horizontal."
 

1. What does it mean for an object to be at rest?

When we say an object is at rest, it means that it is not moving or changing its position in space. In other words, its velocity is zero.

2. What is initial velocity?

Initial velocity, also known as initial speed, is the velocity of an object at the beginning of a time interval. It is measured in units of distance per time, such as meters per second (m/s) or feet per second (ft/s).

3. Can an object at rest have an initial velocity greater than zero?

Yes, an object at rest can have an initial velocity greater than zero. This means that the object starts moving from a stationary position with a certain speed or direction.

4. How is initial velocity calculated?

Initial velocity can be calculated by dividing the change in position (displacement) by the change in time during which the object accelerates from rest. This can be represented by the equation: initial velocity = displacement / time interval.

5. What factors can cause an object at rest to have an initial velocity greater than zero?

An object at rest can have an initial velocity greater than zero due to the application of a force, such as a push or a pull. Other factors such as gravity, collisions, or other external forces can also cause an object at rest to have an initial velocity greater than zero.

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