Answer:
6.46393559312 m/s²
Explanation:
Time taken to cover 56 m

Distance covered in 0.42 seconds

From equation of linear motion


The minimum acceleration is 6.46393559312 m/s²
KE = 1/2 * m * v^2
KE = 1/2 * 0.135 * 40^2
KE = 1/2 * 0.135 * 1600
KE = 108 J
Answer:
it will be 1/√2 of its original period.
Explanation: