Question

After a tornado, a piece of plastic (m=0.2kg) was found embedded in tree depth of 0.035m. Average force applied by tree to stop piece of plastic was 40N.

Q. What is the speed of straw when it hit tree?

- Could you please include energy flow diagram for this question?

Answer 1

We know from the work energy theorem
Work done = Change in kinetic energy
Force*distance (depth) = Initial kinetic energy - Final kinetic energy
since it is finally stopped therefore the final kinetic energy would be Zero
40*0.035 = (1/2)mv² - 0
where m is mass = 0.2 kg
v is initial speed
40*0.035 = (1/2)*0.2*v²
v = 3.742 m/s
Hence the speed of the straw when it hits the tree would be 3.742 m/s

Total energy Energy (E) inetic energy Distance (x)