Average acceleration is defined as

here



now for x direction we can say



Similarly for Y direction



so above is the acceleration in x and y directions
Answer: 
Explanation:
Given
Mass of hockey puck 
Initial velocity of hockey puck is 
First a horizontal force of
is applied to the right for 
acceleration associated with it is

Using equation of motion i.e.

(b) When a force of
is applied for 0.05s
Using equation of motion i.e.

Answer:
thermal conductivity = 0.2906 W/m.K
Explanation:
thermal conductivity = 0.168 BTU/h.ft⁰F
1 BTU/h.ft⁰F = 1.7295772056 W/m.k
0.168 BTU/h.ft⁰F = 0.168 * 1.7295772056 W/m.k
0.168 BTU/h.ft⁰F = 0.2906 W/m.k
As per initial given conditions first we will find the initial potential energy of the feather






now we know that few amount of its initial energy is lost in form of frictional energy loss
so remaining energy will be less than the initial potential energy
So final answer would be
<u><em>A. KE < 0.0196 J</em></u>