Calculate the time of the impact of this force

In summary, the conversation is about calculating the time of impact for a 5 KG force of 20 Newton in a counter direction to the direction of movement with a speed of 4 m/s. The participants discuss the initial and final velocities and the possibility of a positive time. The book's answer of 1.5 seconds is questioned.
  • #1
UNknown 2010
77
0
Hi my question is :

Moving the body mass was affected in 5 KG force of 20 Newton in a counter direction to the direction of movement if the speed 4 m / s. Calculate the time of the impact of this force
is it right?

pi= mvi
= (5)(9)=40 kg.m|s
pf= mvf
= (5)(-4)=-20 kg.m|s
t = (pf - pi)|f
= (-20-45)|20 = -3.25 s
 
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  • #2


Was the initial velocity + 9 m/s and the final velocity - 4 m/s? If so, then OK. (But the time will be positive.)
 
  • #3


yeh (velocity + 9 m/s and the final velocity - 4 m/s)
but my answer is wrong because the time is not positive
can anybody help me ?!
 
  • #4


UNknown 2010 said:
but my answer is wrong because the time is not positive
Done correctly, the time will be positive.

Note: The force is negative.
 
  • #5


In the book the answer was 1.5 seconds. but how they answer it I don't know
 
  • #6


UNknown 2010 said:
In the book the answer was 1.5 seconds. but how they answer it I don't know
Based on the data you provided, that answer seems incorrect. Can you post the problem exactly as given, word for word?

(What book is this from?)
 

FAQ: Calculate the time of the impact of this force

How do you calculate the time of impact of a force?

To calculate the time of impact of a force, you need to know the mass of the object being impacted, the acceleration of the object, and the initial velocity of the object. You can use the equation t = (vf - vi) / a, where t is the time of impact, vf is the final velocity, vi is the initial velocity, and a is the acceleration.

Can you calculate the time of impact without knowing the mass of the object?

No, the mass of the object is a crucial component in calculating the time of impact of a force. Without knowing the mass, you cannot accurately determine the final velocity and therefore cannot calculate the time of impact.

How does the direction of the force impact the time of impact?

The direction of the force does not directly impact the time of impact. However, it does affect the acceleration of the object, which is necessary for calculating the time of impact. Forces in the same direction as the initial velocity will increase the acceleration and decrease the time of impact, while forces in the opposite direction will decrease the acceleration and increase the time of impact.

What units are used to measure time of impact?

The units used to measure time of impact depend on the units used for the other variables in the equation. If the mass is in kilograms, the acceleration in meters per second squared, and the velocity in meters per second, the time of impact will be measured in seconds.

How accurate is the calculation of time of impact?

The accuracy of the calculation of time of impact depends on the accuracy of the values used for the other variables in the equation. If the values are measured or estimated with significant errors, the calculated time of impact will also have a significant error. Additionally, the equation assumes a constant acceleration, which may not be the case in real-world scenarios, leading to a less accurate calculation of time of impact.

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