Newton's 2nd Law: Doubling Force, Double Speed?

AI Thread Summary
Doubling the force applied to the arrow increases its acceleration, but it does not directly double the final speed due to the relationship between acceleration, time, and distance. The key equation to consider is that acceleration is the change in velocity over time, and without a specified time frame, the final speed cannot be simply calculated by doubling the initial speed. The discussion highlights the importance of understanding the kinematic equations that relate acceleration, time, and distance to determine final speed. The confusion arises from assuming a linear relationship between force and speed without considering the effects of time and distance traveled. Thus, the final speed of the arrow, when force is doubled, is 35.4 m/s, illustrating the complexities of motion under varying forces.
gxinxing
Messages
4
Reaction score
0

Homework Statement


An arrow, starting from rest, leaves the bow with a speed of 25 m/s. If the average force exerted on the arrow would be doubled, all else remains the same, with what speed would the arrow leave the bow?

Homework Equations


force = mass x acceleration


The Attempt at a Solution


Since the mass is constant, I assumed that there's a direct relationship between force and acceleration (in this case, speed, since I believe time is irrelevant) so a doubled force should have resulted in doubled acceleration (50 m/s/time). But the answer is 35.4. Why is that?
 
Physics news on Phys.org
The acceleration is doubled, but the speed was asked.

ehild
 
How do I figure out the speed without a given time?
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »

Similar threads

Rocket acceleration problem: confused about Newton's 2nd Law
Replies
42
Views
5K
Newton's 2nd Law: Why is Resistance Considered a Positive Force?
Replies
3
Views
2K
Unbalanced force to find altitude of airplane
Replies
4
Views
2K
Having a hard time learning Newton's 2nd law
Replies
5
Views
2K
Newton's law problem: Helicopter lifting a box with a rope
Replies
5
Views
3K
Newton's Laws Homework question: Double incline mass problem
Replies
4
Views
2K
Calculating acceleration of a prism and block connected to a wall through a rope and pulley
Replies
4
Views
395
Understanding Newton's 2nd Law of Motion
Replies
6
Views
2K
Two forces acting on an object given in vectors - SOLVED
Replies
1
Views
1K
Rank forces according to magnitude: Newton's 2nd/3rd laws
Replies
5
Views
7K

Hot Threads

Recent Insights

Back
Top