Vijay's Reflex Time When Arvind Drops a Scale

[ritwik06]

arvind drops a scale vertically which is grabbed by Vijay whose hand is just below the scale. In the mean time the scale slips by 20cm. What is the reflex time of Vijay?

 

[cristo]

Do you know any equations that may help you here? (hint: constant acceleration).

Is there a reason why this is in the tutorial forum? In future please post in the homework forum.

 

[ritwik06]

Do you know any equations that may help you here? (hint: constant acceleration).

Is there a reason why this is in the tutorial forum? In future please post in the homework forum.

yes, the acceleration will be 9.8 m/sec^2. But how will this help?

oh! I am sorry once again. I haven't understood till now, as to which question should I post in which section. I am sorry again.

 

[cristo]

yes, the acceleration will be 9.8 m/sec^2. But how will this help?

Correct. Do you know any equations that will help you here? You are told the displacement, and you know that the initial velocity is zero.

oh! I am sorry once again. I haven't understood till now, as to which question should I post in which section. I am sorry again.

That's ok. I'm sure it'll be moved for you soon anyway! In future though, use the homework forum. It's the second forum in the list on the front page (just under the tutorial forum)

 

[ritwik06]

Correct. Do you know any equations that will help you here? You are told the displacement, and you know that the initial velocity is zero.



That's ok. I'm sure it'll be moved for you soon anyway! In future though, use the homework forum. It's the second forum in the list on the front page (just under the tutorial forum)

Nope which equation are you talking about?

Ok! I will use the homework section. Thanks!

sorry once again.

 

[cristo]

Have you come across the kinematic equations, for constant acceleration? Here's a link to them (scroll about half way down the page): http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/1DKin/U1L6a.html . Which one do you think is most useful in this case?

 

[ritwik06]

Have you come across the kinematic equations, for constant acceleration? Here's a link to them (scroll about half way down the page): http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/1DKin/U1L6a.html . Which one do you think is most useful in this case?

will the 3rd one help? I have not studdied kinematics yet :S

 

[cristo]

will the 3rd one help? I have not studdied kinematics yet :S

Ok, well you should use the first equation:$$d=v_it+\frac{1}{2}at^2$$. Here, note that v_i=0, so this simplifies the equation somewhat. a is the acceleration due the gravity (9.81), d is the distance measured on the ruler, and t is the reaction time that you require.